ci(kitchen+travis): modify matrix to include `develop` platform

* Use balanced matrix based on `template-formula` guidelines
* Initial ref: https://github.com/saltstack-formulas/template-formula/issues/118

.cirrus.yml

   name: Test $INSTANCE
   env:
     matrix:
-      - INSTANCE: debian-9
-      - INSTANCE: debian-8
-      - INSTANCE: ubuntu-1804
-      - INSTANCE: ubuntu-1604
+      - INSTANCE: default-debian-9-develop-py3
+      - INSTANCE: default-ubuntu-1804-develop-py3
+      # - INSTANCE: default-centos-7-develop-py3
+      # - INSTANCE: default-fedora-29-develop-py3
+      # - INSTANCE: default-opensuse-leap-15-develop-py3
+      - INSTANCE: default-debian-9-2019-2-py3
+      - INSTANCE: default-ubuntu-1804-2019-2-py3
+      # - INSTANCE: default-centos-7-2019-2-py3
+      # - INSTANCE: default-fedora-29-2019-2-py3
+      # - INSTANCE: default-opensuse-leap-15-2019-2-py3
+      - INSTANCE: default-debian-9-2018-3-py2
+      # - INSTANCE: default-ubuntu-1604-2018-3-py2
+      # - INSTANCE: default-centos-7-2018-3-py2
+      # - INSTANCE: default-fedora-29-2018-3-py2
+      # TODO: Use this when fixed instead of `opensuse-leap-42`
+      # Ref: https://github.com/netmanagers/salt-image-builder/issues/2
+      # - INSTANCE: default-opensuse-leap-15-2018-3-py2
+      # - INSTANCE: default-opensuse-leap-42-2018-3-py2
+      # - INSTANCE: default-debian-8-2017-7-py2
+      # - INSTANCE: default-ubuntu-1604-2017-7-py2
+      # TODO: Enable after improving the formula to work with other than `systemd`
+      # - INSTANCE: default-centos-6-2017-7-py2
+      # - INSTANCE: default-fedora-28-2017-7-py2
+      # - INSTANCE: default-opensuse-leap-42-2017-7-py2
   bundle_install_script: bundle install
   verify_script: bundle exec kitchen verify $INSTANCE

kitchen.yml

 # Make sure the platforms listed below match up with
 # the `env.matrix` instances defined in `.travis.yml`
 platforms:
-  - name: debian-9
-    driver_config:
-      image: debian:9
+  ## SALT `develop`
+  - name: debian-9-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:debian-9
       provision_command:
-        - apt-get update && apt-get install -y udev locales
-        - echo "en_US.UTF-8 UTF-8" >> /etc/locale.gen
-        - locale-gen en_US.UTF-8
-      platform: debian
-
-  - name: debian-8
-    driver_config:
-      image: debian:8
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: ubuntu-1804-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:ubuntu-18.04
       provision_command:
-        - apt-get update && apt-get install -y udev locales
-        - echo "en_US.UTF-8 UTF-8" >> /etc/locale.gen
-        - locale-gen en_US.UTF-8
-      platform: debian
-
-  - name: ubuntu-18.04
-    driver_config:
-      image: ubuntu:18.04
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: centos-7-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:centos-7
       provision_command:
-        - apt-get update && apt-get install -y udev locales && rm -rf /var/lib/apt/lists/*
-        - localedef -i en_US -c -f UTF-8 -A /usr/share/locale/locale.alias en_US.UTF-8
-        - echo "en_US.UTF-8 UTF-8" >> /etc/locale.gen
-        - locale-gen en_US.UTF-8
-      platform: ubuntu
-
-  - name: ubuntu-16.04
-    driver_config:
-      image: ubuntu:16.04
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: fedora-29-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:fedora-29
+      provision_command:
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: opensuse-leap-15-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:opensuse-leap-15
       provision_command:
-        - apt-get update && apt-get install -y udev locales && rm -rf /var/lib/apt/lists/*
-        - localedef -i en_US -c -f UTF-8 -A /usr/share/locale/locale.alias en_US.UTF-8
-        - echo "en_US.UTF-8 UTF-8" >> /etc/locale.gen
-        - locale-gen en_US.UTF-8
-      platform: ubuntu
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+      run_command: /usr/lib/systemd/systemd
+
+  ## SALT 2019.2
+  - name: debian-9-2019-2-py3
+    driver:
+      image: netmanagers/salt-2019.2-py3:debian-9
+  - name: ubuntu-1804-2019-2-py3
+    driver:
+      image: netmanagers/salt-2019.2-py3:ubuntu-18.04
+  - name: centos-7-2019-2-py3
+    driver:
+      image: netmanagers/salt-2019.2-py3:centos-7
+  - name: fedora-29-2019-2-py3
+    driver:
+      image: netmanagers/salt-2019.2-py3:fedora-29
+  - name: opensuse-leap-15-2019-2-py3
+    driver:
+      image: netmanagers/salt-2019.2-py3:opensuse-leap-15
+      run_command: /usr/lib/systemd/systemd
+
+  ## SALT 2018.3
+  - name: debian-9-2018-3-py2
+    driver:
+      image: netmanagers/salt-2018.3-py2:debian-9
+  - name: ubuntu-1604-2018-3-py2
+    driver:
+      image: netmanagers/salt-2018.3-py2:ubuntu-16.04
+  - name: centos-7-2018-3-py2
+    driver:
+      image: netmanagers/salt-2018.3-py2:centos-7
+  - name: fedora-29-2018-3-py2
+    driver:
+      image: netmanagers/salt-2018.3-py2:fedora-29
+  # TODO: Use this when fixed instead of `opensuse-leap-42`
+  # Ref: https://github.com/netmanagers/salt-image-builder/issues/2
+  # - name: opensuse-leap-15-2018-3-py2
+  #   driver:
+  #     image: netmanagers/salt-2018.3-py2:opensuse-leap-15
+  #     run_command: /usr/lib/systemd/systemd
+  - name: opensuse-leap-42-2018-3-py2
+    driver:
+      image: netmanagers/salt-2018.3-py2:opensuse-leap-42
+      run_command: /usr/lib/systemd/systemd
+
+  ## SALT 2017.7
+  - name: debian-8-2017-7-py2
+    driver:
+      image: netmanagers/salt-2017.7-py2:debian-8
+  - name: ubuntu-1604-2017-7-py2
+    driver:
+      image: netmanagers/salt-2017.7-py2:ubuntu-16.04
+  # TODO: Modify the formula to work for non-`systemd` platforms
+  - name: centos-6-2017-7-py2
+    driver:
+      image: netmanagers/salt-2017.7-py2:centos-6
+      run_command: /sbin/init
+  - name: fedora-28-2017-7-py2
+    driver:
+      image: netmanagers/salt-2017.7-py2:fedora-28
+  - name: opensuse-leap-42-2017-7-py2
+    driver:
+      image: netmanagers/salt-2017.7-py2:opensuse-leap-42
+      run_command: /usr/lib/systemd/systemd
 
 provisioner:
   name: salt_solo
   log_level: info
-  salt_version: latest
+  salt_install: none
   require_chef: false
   formula: syslog_ng
   salt_copy_filter:
     base:
       '*':
         - syslog_ng.config
+  pillars:
+    top.sls:
+      base:
+        '*':
+          - syslog_ng
+  pillars_from_files:
+    syslog_ng.sls: pillar.example
 
 verifier:
   # https://www.inspec.io/