Added YAML linting

Author: rimi-itk

config/symfony/yaml/.prettierrc.yaml

@@ -0,0 +1,8 @@
+# https://prettier.io/docs/configuration
+overrides:
+  # Symfony config
+  - files:
+      - "config/**/*.{yml,yaml}"
+    options:
+      tabWidth: 4
+      singleQuote: true

docs/github-actions-templates.md

@@ -1,6 +1,6 @@
 <!-- DO NOT EDIT THIS FILE!
 
-It was automatically created at 2025-05-20T13:49:11+02:00
+It was automatically created at 2025-06-12T14:50:42+02:00
 by task/scripts/github-documentation-update
 based on /app/task/scripts/../templates/github-actions-templates.md
 -->
@@ -299,6 +299,26 @@ Validates Twig files
 
 ---
 
+[github/workflows/yaml.yaml](github/workflows/yaml.yaml)
+
+### YAML
+
+Validates YAML files.
+
+#### Assumptions
+
+1. A docker compose service named `prettier` for running
+   [Prettier](https://prettier.io/) exists.
+
+#### Symfony YAML
+
+Symfony's YAML config files use 4 spaces for indentation and single quotes.
+Therefore we use a [Prettier configuration
+file](https://prettier.io/docs/configuration), `.prettierrc.yaml`, to make
+Prettier format YAML files in the `config/` folder like Symfony expects.
+
+---
+
 ## Updating template documentation
 
 To update this document, run

github/workflows/yaml.yaml

@@ -0,0 +1,40 @@
+# Do not edit this file! Make a pull request on changing
+# github/workflows/yaml.yaml in
+# https://github.com/itk-dev/devops_itkdev-docker if need be.
+
+### ### YAML
+###
+### Validates YAML files.
+###
+### #### Assumptions
+###
+### 1. A docker compose service named `prettier` for running
+###    [Prettier](https://prettier.io/) exists.
+###
+### #### Symfony YAML
+###
+### Symfony's YAML config files use 4 spaces for indentation and single quotes.
+### Therefore we use a [Prettier configuration
+### file](https://prettier.io/docs/configuration), `.prettierrc.yaml`, to make
+### Prettier format YAML files in the `config/` folder like Symfony expects.
+
+name: YAML
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+      - develop
+
+jobs:
+  yaml-lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - run: |
+          docker network create frontend
+
+      - run: |
+          docker compose run --rm prettier '**/*.{yml,yaml}' --check

templates/drupal-10/.github/workflows/yaml.yaml

@@ -0,0 +1 @@
+../../../../github/workflows/yaml.yaml

templates/drupal-11/.github/workflows/yaml.yaml

@@ -0,0 +1 @@
+../../../../github/workflows/yaml.yaml

templates/drupal-7/.github/workflows/yaml.yaml

@@ -0,0 +1 @@
+../../../../github/workflows/yaml.yaml

templates/drupal-8/.github/workflows/yaml.yaml

@@ -0,0 +1 @@
+../../../../github/workflows/yaml.yaml

templates/drupal-9/.github/workflows/yaml.yaml

@@ -0,0 +1 @@
+../../../../github/workflows/yaml.yaml

templates/drupal-module/.github/workflows/yaml.yaml

@@ -0,0 +1 @@
+../../../../github/workflows/yaml.yaml

templates/symfony-3/.github/workflows/yaml.yaml

@@ -0,0 +1 @@
+../../../../github/workflows/yaml.yaml