Add HTML link checker

.github/workflows/ci.yml

@@ -1,4 +1,4 @@
-name: CI
+name: Build and Test
 
 on:
   push:
@@ -11,7 +11,7 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  build:
+  build-and-test:
     runs-on: ubuntu-latest
 
     steps:
@@ -35,3 +35,9 @@ jobs:
 
     - name: Build Astro project
       run: npm run build
+
+    - name: Run HTML Link test
+      run: |
+        curl https://htmltest.wjdp.uk | bash
+        echo "IgnoreDirectoryMissingTrailingSlash: True" > .htmltest.yml
+        ./bin/htmltest --conf .htmltest.yml --skip-external dist