ci: Add yamllint pass

Signed-off-by: Christoph Heiss <christoph@c8h4.io>

.github/workflows/build.yml

@@ -1,14 +1,24 @@
+---
 name: Lint and build
 
-on:
-  push:
-    branches:
-      - main
-      - dev
+on: push  # yamllint disable-line rule:truthy
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.11'
+      - run: pip install yamllint
+      - run: yamllint --strict .
+
   docker-image:
     runs-on: ubuntu-latest
+    needs: lint
+    timeout-minutes: 5
     steps:
       - uses: actions/checkout@v3
       - uses: docker/setup-buildx-action@v2

.yamllint

@@ -0,0 +1,5 @@
+---
+extends: default
+
+yaml-files:
+  - '**/*.yml'

config.yml

@@ -1,3 +1,4 @@
+---
 baseURL: https://c8h4.io/
 languageCode: en-us
 title: Christoph Heiss

themes/hacker/theme.yml

@@ -1,3 +1,4 @@
+---
 name: Hacker
 homepage: https://github.com/christoph-heiss/christoph-heiss.at
 min_version: 0.41.0