[FLINK-34732][cdc][ci] Add document dead link check for Flink CDC Doc…

…umentation

.dlc.json

@@ -0,0 +1,35 @@
+{
+  "ignorePatterns": [
+    {
+      "pattern": "^http://localhost"
+    },
+    {
+      "pattern": "^https://mvnrepository.com"
+    },
+    {
+      "pattern": "^https://img.shields.io"
+    },
+    {
+      "pattern": "^https://tokei.rs"
+    },
+    {
+      "pattern": "^https://json.org/"
+    },
+    {
+      "pattern": "^https://opencollective.com"
+    },
+    {
+      "pattern": "^https://twitter.com*"
+    }
+  ],
+  "timeout": "30s",
+  "retryOn429": true,
+  "retryCount": 10,
+  "fallbackRetryDelay": "1000s",
+  "aliveStatusCodes": [
+    0,
+    200,
+    401,
+    403
+  ]
+}

.github/workflows/build_docs.yml

@@ -16,6 +16,12 @@
 name: "Build documentation"
 
 on:
+  pull_request:
+    branches:
+      - master
+      - release-*
+    paths:
+      - 'docs/**'
   push:
     paths:
       - 'docs/**'
@@ -30,8 +36,22 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+
+  dead-link-check:
+    if: github.event_name == 'pull_request'
+    name: Dead links
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v3
+      - run: sudo npm install -g markdown-link-check@3.10.3
+      - run: |
+          for file in $(find . -name "*.md"); do
+            markdown-link-check -c .dlc.json -q "$file"
+          done
+
   build-documentation:
-    if: github.repository == 'apache/flink-cdc'
+    if: github.event_name != 'pull_request' && github.repository == 'apache/flink-cdc'
     runs-on: ubuntu-latest
     strategy:
       max-parallel: 1