ci: Restore link checker

Author: deandreamatias

.github/workflows/base.yaml

@@ -22,10 +22,10 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
-      # - name: Check broken links
-      #   uses: JustinBeckwith/linkinator-action@v1
-      #   with:
-      #     paths: "**/*.md"
+      - name: Check broken links
+        uses: JustinBeckwith/linkinator-action@v1
+        with:
+          paths: "**/*.md"
 
       - name: Flutter action
         uses: subosito/flutter-action@v2