CI: Use lychee cf. Linkspector for checking links

Author: alexdewar

.github/workflows/check-links.yml

@@ -9,12 +9,9 @@ on:
 
 jobs:
   check-links:
-    name: Linkspector
+    name: Lychee link checker
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
-      - name: Run linkspector
-        uses: umbrelladocs/action-linkspector@v1
-        with:
-          github_token: ${{ secrets.github_token }}
-          reporter: github-pr-review
+      - id: lychee
+        uses: lycheeverse/lychee-action@v2