Update gradle.yml

Author: zzdh8

.github/workflows/gradle.yml

@@ -54,6 +54,8 @@ jobs:
          sudo docker pull ${{ secrets.DOCKER_USERNAME }}/sohwakhaeng:${GITHUB_SHA::7}
          sudo docker tag ${{ secrets.DOCKER_USERNAME }}/sohwakhaeng:${GITHUB_SHA::7} sohwakhaeng
          sudo docker-compose up -d
+         sudo docker image prune -f
+         
 
   dependency-submission: