Add PR Docs Link Check workflow

Author: nhussein11

.github/workflows/check-pr-labels.yml

@@ -0,0 +1,13 @@
+name: 'PR Docs Link Check'
+
+on:
+  pull_request:
+
+jobs:
+  check-docs-links:
+    uses: papermoonio/workflows/.github/workflows/pr-blocked-label.yml@main
+    with:
+      mkdocs_repo: papermoonio/polkadot-mkdocs
+      docs_repo: polkadot-developers/polkadot-docs
+      docs_checkout: polkadot-docs
+      url: https://docs.polkadot.com