Add GitHub workflow to check internal links

.github/workflows/lint_jekyll.yaml

@@ -0,0 +1,40 @@
+name: Lint Jekyll site
+
+on: [push, pull_request]
+
+jobs:
+  check-internal-links:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: docs
+    steps:
+      - uses: actions/checkout@v3
+      - uses: ruby/[email protected]
+        with:
+          ruby-version: '3.3'
+          bundler-cache: true
+          cache-version: 0
+      - name: Setup Pages
+        id: pages
+        uses: actions/configure-pages@v3
+      - name: Install dependencies
+        run: |
+          bundle install
+      - name: Build with Jekyll
+        # Outputs to the './_site' directory by default
+        run: |
+          bundle exec jekyll build --baseurl "${{ steps.pages.outputs.base_path }}"
+        env:
+          JEKYLL_ENV: production
+      - name: Validate HTML and check links
+        run: |
+          bundle exec htmlproofer \
+            --allow_missing_href=true \
+            --ignore-urls "/.*localhost.*/","/.*gitter\.im.*/" \
+            --enforce-https=false  \
+            --disable-external=true \
+            --ignore_empty_alt=true \
+            --ignore_missing_alt=true \
+            --check-internal-hash=false \
+            ./_site