Add Javadoc build workflow

Signed-off-by: Arthit Suriyawongkul <arthit@gmail.com>

Author: bact

.github/workflows/docs.yml

@@ -0,0 +1,36 @@
+name: Generate and publish API JavaDocs
+
+on:
+  push:
+    branches: [ master ]
+
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8  # v5.0.0
+      with:
+        fetch-depth: 0
+
+    - name: Set up JDK
+      uses: actions/setup-java@dded0888837ed1f317902acf8a20df0ad188d165  # v5.0.0
+      with:
+        distribution: 'temurin'
+        java-version: 17
+
+    - name: Cache Maven packages
+      uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4.3.0
+      with:
+        path: ~/.m2
+        key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}
+
+    - name: Generate docs
+      run: mvn javadoc:javadoc
+
+    - name: Deploy docs
+      uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e  # v4.0.0
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        publish_dir: ./target/reports/apidocs