install docker

Author: JoeWang1127

.cloudbuild/library_generation/cloudbuild-library-generation-integration-test.yaml

@@ -37,6 +37,7 @@ steps:
     - |
       apt-get update
       apt-get -y install maven
+      apt-get -y install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
       pip install --upgrade pip
       pip install --require-hashes -r hermetic_build/common/requirements.txt
       pip install hermetic_build/common