Bumped linkinator-action to now-working v2.4.0

Author: adamlui

.github/workflows/validate-links-on-push-pr.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v6.0.2
-      - uses: JustinBeckwith/linkinator-action@v1
+      - uses: JustinBeckwith/linkinator-action@v2.4.0
         with:
           paths: '**/*.md'
           statusCodes: '{ "429": "skip" }'