build javadoc in CI, create a zip of it, and upload the zip to github.

.github/workflows/ant.yml

@@ -12,9 +12,9 @@ jobs:
     steps:
       - name: GetText
         run: sudo apt install gettext
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Set up JDK 8
-        uses: actions/setup-java@v2
+        uses: actions/setup-java@v4
         with:
           java-version: '8'
           distribution: 'temurin'
@@ -26,9 +26,35 @@ jobs:
       - name: build with Ant
         run: ant distclean pkg
       - name: Upload installer.jar
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: I2P-install.jar-${{ github.sha }}
           path: install.jar
-        
+  
+  javadoc-latest:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: GetText
+        run: sudo apt install gettext
+      - uses: actions/checkout@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+      - name : Generate override.properties
+        run: |
+          rm -f override.properties
+          echo "build.built-by=GitHub Actions" >> override.properties
+          echo "noExe=true" >> override.properties
+      - name: build with Ant
+        run: ant distclean javadoc
+      - name: zip javadoc
+        run: zip -r javadoc.zip build/javadoc
+      - name: Upload javadoc.zip
+        uses: actions/upload-artifact@v4
+        with:
+          name: I2P-javadoc-${{ github.sha }}.zip
+          path: javadoc.zip