added a link-check ci

Author: Gmin2

.github/workflows/link-check.yml

@@ -0,0 +1,23 @@
+name: Link Checker
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    types: [opened, synchronize, reopened]
+  workflow_dispatch:
+
+jobs:
+  linkinator:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v2
+
+      - name: Validate Links in Markdown Files
+        uses: JustinBeckwith/linkinator-action@v1
+        with:
+          paths: "pages/blog/posts/**/*.md"
+          markdown: true
+          retry: true