push.yml: remove redundant "chmod" steps

Author: stephengold

.github/workflows/push.yml

@@ -15,7 +15,6 @@ jobs:
           distribution: 'zulu'
           java-version: 11
       - uses: gradle/actions/wrapper-validation@v5
-      - run: chmod +x gradlew
       - run: ./gradlew javadoc build --console=plain --no-daemon --stacktrace
 
   Java17-MacOS:
@@ -27,7 +26,6 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: 17
-      - run: chmod +x gradlew
       - run: ./gradlew javadoc build --console=plain --no-daemon --stacktrace
 
   Java21-Windows: