[hotfix][ci] Exclude Flink compatibility modules from Javadocs generation (#4470)

* [ci] Exclude Flink compatibility modules from Javadoc

* [ci] Run documentation checks for workflow changes

Author: yuxiqian

.github/workflows/build_docs.yml

@@ -22,6 +22,8 @@ on:
       - release-*
     paths:
       - 'docs/**'
+      - '.github/workflows/build_docs.yml'
+      - '.github/workflows/docs.sh'
   schedule:
     - cron: '0 0 * * *' # Deploy every day
   workflow_dispatch:

.github/workflows/docs.sh

@@ -54,7 +54,9 @@ mvn clean install -B -DskipTests -Dfast
 
 # build java/scala docs
 mkdir -p docs/target/api
+# Compatibility modules target different Flink versions and cannot share a Javadoc classpath.
 mvn javadoc:aggregate -B \
+    -pl '!flink-cdc-flink1-compat,!flink-cdc-flink2-compat' \
     -DadditionalJOption="-Xdoclint:none --allow-script-in-comments" \
     -Dmaven.javadoc.failOnError=false \
     -Dcheckstyle.skip=true \