Run yamllint with strict mode, fix issue (go-gitea#33551)

Previously yamllint would issue warnings for certain things, while still
exiting with zero. Now warnings are treated like errors and will cause
non-zero exit:

```
  -s, --strict          return non-zero exit code on warnings as well as errors
```

Author: silverwind

.github/workflows/cron-licenses.yml

@@ -1,8 +1,8 @@
 name: cron-licenses
 
 on:
-  #schedule:
-  #  - cron: "7 0 * * 1" # every Monday at 00:07 UTC
+  # schedule:
+  #   - cron: "7 0 * * 1" # every Monday at 00:07 UTC
   workflow_dispatch:
 
 jobs:

Makefile

@@ -393,7 +393,7 @@ lint-templates: .venv node_modules ## lint template files
 
 .PHONY: lint-yaml
 lint-yaml: .venv ## lint yaml files
-	@poetry run yamllint .
+	@poetry run yamllint -s .
 
 .PHONY: watch
 watch: ## watch everything and continuously rebuild