FIX - PR changes to tidy up after ourselves

Author: springdo

jenkins-slaves/jenkins-slave-gradle/Dockerfile

@@ -7,7 +7,8 @@ USER root
 RUN curl -skL -o /tmp/gradle-bin.zip https://services.gradle.org/distributions/gradle-$GRADLE_VERSION-bin.zip && \
     mkdir -p /opt/gradle && \
     unzip -q /tmp/gradle-bin.zip -d /opt/gradle && \
-    ln -sf /opt/gradle/gradle-$GRADLE_VERSION/bin/gradle /usr/local/bin/gradle
+    ln -sf /opt/gradle/gradle-$GRADLE_VERSION/bin/gradle /usr/local/bin/gradle && \
+    rm -f /tmp/gradle-bin.zip
 
 RUN chown -R 1001:0 /opt/gradle && \
     chmod -R g+rw /opt/gradle