suggest linting yaml-files

.github/workflows/yamllint.yaml

@@ -0,0 +1,20 @@
+---
+name: 'Yamllint GitHub Actions'
+
+# yamllint disable-line rule:truthy
+on: [push, pull_request]
+
+jobs:
+  yamllint:
+    name: 'Yamllint'
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Checkout'
+        uses: actions/checkout@master
+      - name: 'Yamllint'
+        uses: karancode/yamllint-github-action@master
+        with:
+          yamllint_file_or_dir: '.'
+          yamllint_config_filepath: './.yamllint'
+          yamllint_strict: false
+          yamllint_comment: true

.yamllint

@@ -0,0 +1,8 @@
+---
+extends: default
+
+rules:
+  # 150 chars should be enough, but don't fail if a line is longer
+  line-length:
+    max: 180
+    level: warning

_config.yml

@@ -1,3 +1,4 @@
+---
 title: Verschwörhaus bleibt
 description: Offener Brief an die Stadtverwaltung Ulm
 
@@ -14,31 +15,30 @@ footer:
 footer_custom: 'Der Text dieses Briefes wurde unter CC BY-SA veröffentlicht.'
 
 layout:
-  theme: default # default, vintage, nord
-  theme_switch: true # enable or disable user toggle switch between light and dark theme
-  link_new_tab: true # should external links open in a new tab (true) or in the current tab (false)
+  theme: default  # default, vintage, nord
+  theme_switch: true  # enable or disable user toggle switch between light and dark theme
+  link_new_tab: true  # should external links open in a new tab (true) or in the current tab (false)
 
 # styles
 # include only the styles you want [true | false]
 styles:
-  font_family: sans # serif, sans (default)
+  font_family: sans  # serif, sans (default)
   forms: true
 
 markdown: kramdown
 highlighter: rouge
 
 permalink: pretty
-permalink: /:title/
 
 sass:
   sass_dir: /assets/css/_sass
-  style: compressed # nested, compact, expanded or compressed
+  style: compressed  # nested, compact, expanded or compressed
   sourcemap: never
 
 plugins:
- - jekyll-optional-front-matter # https://github.com/benbalter/jekyll-optional-front-matter
- - jekyll-titles-from-headings # https://github.com/benbalter/jekyll-titles-from-headings/
- - jekyll-seo-tag
+  - jekyll-optional-front-matter  # https://github.com/benbalter/jekyll-optional-front-matter
+  - jekyll-titles-from-headings  # https://github.com/benbalter/jekyll-titles-from-headings/
+  - jekyll-seo-tag
 
 titles_from_headings:
   enabled: true
@@ -59,4 +59,4 @@ exclude:
   - README.*
   - server
   - vendor/
-  - .sass-cache/
+  - .sass-cache/

_data/authors.yml

@@ -1,4 +1,5 @@
+---
 - name: Eduard Itrich
 - name: Stefan Kraus
 - name: Jan-Ole Beyer
-- name: Jerg Theurer
+- name: Jerg Theurer

_data/organizations.yml

@@ -1,3 +1,4 @@
+---
 - name: Open Knowledge Foundation Deutschland e.V.
   logo: /assets/okfn.svg
 - name: Verwaltungsrebellen
@@ -7,4 +8,4 @@
 - name: Verbund Offener Werkstätten e.V.
   logo: /assets/verbund-offener-werkstaetten-logo.png
 - name: Eigenbaukombinat Halle e.V.
-  logo: /assets/eigenbaukombinat-logo.png
+  logo: /assets/eigenbaukombinat-logo.png

_data/signees.yml

@@ -1,3 +1,4 @@
+---
 - name: Bianca Kastl
 - name: Lilith Wittmann
 - name: Marco Holz
@@ -28,8 +29,8 @@
 - name: Peter Kuhn
 - name: Teal Bauer
 - name: Peter Onderscheka
-- name: Tatiana Muñoz 
-- name: Nana Schön 
+- name: Tatiana Muñoz
+- name: Nana Schön
 - name: Emmanouil 'madonius' Kampitakis
 - name: Timo Widdau
 - name: Lilian Roller