Add broken link check

.github/workflows/gh-pages.yml

@@ -1,6 +1,7 @@
 name: github pages
 
 on:
+  workflow_dispatch:
   push:
     branches:
       - next-major-release
@@ -26,3 +27,20 @@ jobs:
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./public
+
+  broken_link_checker_job:
+    runs-on: ubuntu-latest
+    name: Check for broken links
+    steps:
+      - name: Check for broken links
+        id: link-report
+        uses: celinekurpershoek/link-checker@v1.0.1
+        with:
+          # Required:
+          url: 'https://opm.github.io/ResInsight-UserDocumentation/'
+          # optional:
+          honorRobotExclusions: false
+          ignorePatterns: ''
+          recursiveLinks: false # Check all URLs on all reachable pages (could take a while)
+      - name: Get the result
+        run: echo "${{steps.link-report.outputs.result}}"