fix setup-java action

Author: Andre601

.github/workflows/generate_javadoc.yml

@@ -17,6 +17,7 @@ jobs:
     - name: Set up Java 11
       uses: actions/setup-java@v2
       with:
+        distribution: 'adobt'
         java-version: 1.11
     - name: Generate Javadoc
       run: ./gradlew javadoc
@@ -36,6 +37,7 @@ jobs:
     - name: Set up Java 11
       uses: actions/setup-java@v2
       with: 
+        distribution: 'adobt'
         java-version: 1.11
     - name: Generate Jars
       run: ./gradlew build