fix CI docker container clean up issue (#1917)

Signed-off-by: chensuyue <[email protected]>

Author: chensuyue

.azure-pipelines/template/docker-template.yml

@@ -36,7 +36,7 @@ steps:
   - ${{ if eq(parameters.dockerConfigName, 'commonDockerConfig') }}:
       - script: |
           rm -fr ${BUILD_SOURCESDIRECTORY} || sudo rm -fr ${BUILD_SOURCESDIRECTORY} || true
-          echo y | docker system prune --all
+          echo y | docker image prune -a
         displayName: "Clean workspace"
 
       - checkout: self
@@ -48,7 +48,7 @@ steps:
           rm -fr ${BUILD_SOURCESDIRECTORY} || sudo rm -fr ${BUILD_SOURCESDIRECTORY} || true
           mkdir ${BUILD_SOURCESDIRECTORY}
           chmod 777 ${BUILD_SOURCESDIRECTORY}
-          echo y | docker system prune --all
+          echo y | docker image prune -a
         displayName: "Clean workspace"
 
       - checkout: none