Add Markdown lint action

Author: xhanulik

.github/markdownlint-config.json

@@ -0,0 +1,7 @@
+{
+    "default": true,
+    "MD013": false,
+    "MD041": false,
+    "MD014": false,
+    "MD024": false
+}

.github/workflows/markdownlint.yml

@@ -0,0 +1,21 @@
+---
+name: markdownlint
+
+on:
+  pull_request:
+  push:
+
+permissions:
+  contents: read
+
+jobs:
+  markdownlint:
+    name: Check for Markdown errors
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: articulate/actions-markdownlint@v1
+        with:
+          config: .github/markdownlint-config.json
+          files: './*.md'