refactor(yaml): fix yamllint errors, update pillar for tests

diaspora/defaults.yaml

+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
 diaspora:
   systemd:
     web_template: salt://diaspora/files/diaspora-web.service
 
   ruby_version: 2.6.6
 
-  install_redis: True
+  install_redis: true
 
   user:
     username: diaspora
     type: postgresql
     host: localhost
     username: diaspora
-    password:
+    password: ~
     database: diaspora

kitchen.yml

           base:
             '*':
               - diaspora
+              - tests
       pillars_from_files:
         diaspora.sls: pillar.example
+        tests.sls: test/salt/pillar/tests.sls
     verifier:
       inspec_tests:
         - path: test/integration/default

pillar.example

+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
 diaspora:
-  repository: git://github.com/diaspora/diaspora.git
+  repository: https://github.com/diaspora/diaspora.git
 
   # version can be a branch or a tag
   version: develop
 
   install_path: /srv/diaspora
 
-  ruby_version: 2.3.4
+  ruby_version: 2.6.6
+
+  install_redis: false
 
   user:
     username: diaspora
     password: secret
     database: diaspora
 
-  # have a look at https://github.com/diaspora/diaspora/blob/develop/config/diaspora.yml.example
+  # see https://github.com/diaspora/diaspora/blob/develop/config/diaspora.toml.example
   configuration:
     environment:
       url: "https://example.org/"

test/salt/pillar/tests.sls

+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
+diaspora:
+  install_redis: true
+
+  user:
+    shell: /bin/bash