ci: enable yaml checks

.travis.yml

@@ -33,6 +33,7 @@ script:
   - poetry run make style_check
   - poetry run make defs_check
   - poetry run make gen_check
+  - poetry run make yaml_check
   - ci/check_fixup.sh
 
 notifications:

.yamllint.yml

@@ -8,3 +8,6 @@ rules:
   line-length: disable
   # skip "---" at the beginning
   document-start: disable
+  comments-indentation: disable
+  indentation:
+    spaces: 2

Makefile

@@ -39,13 +39,13 @@ pystyle: ## apply code style on application sources and tests
 	@flake8 $(PY_FILES)
 	make -C python style
 
-changelog_check:  # check changelog format
+changelog_check: ## check changelog format
 	./tools/linkify-changelogs.py --check
 
-yaml_check:
+yaml_check: ## check yaml formatting
 	yamllint .
 
-changelog:  # fill out issue links in changelog
+changelog: ## fill out issue links in changelog
 	./tools/linkify-changelogs.py
 
 cstyle_check: ## run code style check on low-level C code

ci/prebuild.yml

@@ -17,6 +17,11 @@ gen prebuild:
   script:
     - nix-shell --run "poetry run make gen_check"
 
+yaml prebuild:
+  stage: prebuild
+  script:
+    - nix-shell --run "poetry run make yaml_check"
+
 release commit messages prebuild:
   stage: prebuild
   before_script: []  # nothing needed