ci: add Debian 11 Bullseye & update `yamllint` configuration [skip ci]

* Automated using https://github.com/myii/ssf-formula/pull/345

.gitlab-ci.yml

 ## Define the rest of the matrix based on Kitchen testing
 # Make sure the instances listed below match up with
 # the `platforms` defined in `kitchen.yml`
+# repositories-debian-11-tiamat-py3: {extends: '.test_instance'}
 # repositories-debian-10-tiamat-py3: {extends: '.test_instance'}
 # repositories-debian-9-tiamat-py3: {extends: '.test_instance'}
 # repositories-ubuntu-2004-tiamat-py3: {extends: '.test_instance'}
 # repositories-ubuntu-1804-tiamat-py3: {extends: '.test_instance'}
+# repositories-debian-11-master-py3: {extends: '.test_instance'}
+# preferences-debian-11-master-py3: {extends: '.test_instance'}
+# unattended-debian-11-master-py3: {extends: '.test_instance'}
+debian-11-master-py3: {extends: '.test_instance'}
 # repositories-debian-10-master-py3: {extends: '.test_instance'}
 # preferences-debian-10-master-py3: {extends: '.test_instance'}
 # unattended-debian-10-master-py3: {extends: '.test_instance'}
 # preferences-ubuntu-1804-master-py3: {extends: '.test_instance'}
 # unattended-ubuntu-1804-master-py3: {extends: '.test_instance'}
 ubuntu-1804-master-py3: {extends: '.test_instance'}
+# repositories-debian-11-3003-1-py3: {extends: '.test_instance'}
 # repositories-debian-10-3003-1-py3: {extends: '.test_instance'}
 # repositories-debian-9-3003-1-py3: {extends: '.test_instance'}
 # repositories-ubuntu-2004-3003-1-py3: {extends: '.test_instance'}
 # repositories-ubuntu-1804-3003-1-py3: {extends: '.test_instance'}
+# repositories-debian-11-3002-6-py3: {extends: '.test_instance'}
 # repositories-debian-10-3002-6-py3: {extends: '.test_instance'}
 # repositories-debian-9-3002-6-py3: {extends: '.test_instance'}
 # repositories-ubuntu-2004-3002-6-py3: {extends: '.test_instance'}

.travis.yml

     ## Define the rest of the matrix based on Kitchen testing
     # Make sure the instances listed below match up with
     # the `platforms` defined in `kitchen.yml`
+    # - env: INSTANCE=repositories-debian-11-tiamat-py3
     # - env: INSTANCE=repositories-debian-10-tiamat-py3
     # - env: INSTANCE=repositories-debian-9-tiamat-py3
     # - env: INSTANCE=repositories-ubuntu-2004-tiamat-py3
     # - env: INSTANCE=repositories-ubuntu-1804-tiamat-py3
+    # - env: INSTANCE=repositories-debian-11-master-py3
+    # - env: INSTANCE=preferences-debian-11-master-py3
+    # - env: INSTANCE=unattended-debian-11-master-py3
+    - env: INSTANCE=debian-11-master-py3
     # - env: INSTANCE=repositories-debian-10-master-py3
     # - env: INSTANCE=preferences-debian-10-master-py3
     # - env: INSTANCE=unattended-debian-10-master-py3
     # - env: INSTANCE=preferences-ubuntu-1804-master-py3
     # - env: INSTANCE=unattended-ubuntu-1804-master-py3
     - env: INSTANCE=ubuntu-1804-master-py3
+    # - env: INSTANCE=repositories-debian-11-3003-1-py3
     # - env: INSTANCE=repositories-debian-10-3003-1-py3
     # - env: INSTANCE=repositories-debian-9-3003-1-py3
     # - env: INSTANCE=repositories-ubuntu-2004-3003-1-py3
     # - env: INSTANCE=repositories-ubuntu-1804-3003-1-py3
+    # - env: INSTANCE=repositories-debian-11-3002-6-py3
     # - env: INSTANCE=repositories-debian-10-3002-6-py3
     # - env: INSTANCE=repositories-debian-9-3002-6-py3
     # - env: INSTANCE=repositories-ubuntu-2004-3002-6-py3

.yamllint

 extends: 'default'
 
 # Files to ignore completely
-# 1. All YAML files under directory `.cache/`, introduced during the GitLab CI run
-# 2. All YAML files under directory `.git/`
-# 3. All YAML files under directory `node_modules/`, introduced during the Travis run
-# 4. Any SLS files under directory `test/`, which are actually state files
-# 5. Any YAML files under directory `.kitchen/`, introduced during local testing
-# 6. `kitchen.vagrant.yml`, which contains Embedded Ruby (ERB) template syntax
+# 1. All YAML files under directory `.bundle/`, introduced if gems are installed locally
+# 2. All YAML files under directory `.cache/`, introduced during the CI run
+# 3. All YAML files under directory `.git/`
+# 4. All YAML files under directory `node_modules/`, introduced during the CI run
+# 5. Any SLS files under directory `test/`, which are actually state files
+# 6. Any YAML files under directory `.kitchen/`, introduced during local testing
+# 7. `kitchen.vagrant.yml`, which contains Embedded Ruby (ERB) template syntax
 ignore: |
+  .bundle/
   .cache/
   .git/
   node_modules/

kitchen.yml

 
 platforms:
   ## SALT `tiamat`
+  - name: debian-11-tiamat-py3
+    driver:
+      image: saltimages/salt-tiamat-py3:debian-11
+      run_command: /lib/systemd/systemd
   - name: debian-10-tiamat-py3
     driver:
       image: saltimages/salt-tiamat-py3:debian-10
       run_command: /lib/systemd/systemd
 
   ## SALT `master`
+  - name: debian-11-master-py3
+    driver:
+      image: saltimages/salt-master-py3:debian-11
+      run_command: /lib/systemd/systemd
   - name: debian-10-master-py3
     driver:
       image: saltimages/salt-master-py3:debian-10
       run_command: /lib/systemd/systemd
 
   ## SALT `3003.1`
+  - name: debian-11-3003-1-py3
+    driver:
+      image: saltimages/salt-3003.1-py3:debian-11
+      run_command: /lib/systemd/systemd
   - name: debian-10-3003-1-py3
     driver:
       image: saltimages/salt-3003.1-py3:debian-10
       run_command: /lib/systemd/systemd
 
   ## SALT `3002.6`
+  - name: debian-11-3002-6-py3
+    driver:
+      image: saltimages/salt-3002.6-py3:debian-11
+      run_command: /lib/systemd/systemd
   - name: debian-10-3002-6-py3
     driver:
       image: saltimages/salt-3002.6-py3:debian-10