add env

Author: JoeWang1127

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

@@ -15,6 +15,7 @@
 timeout: 7200s # 2 hours
 substitutions:
   _TEST_IMAGE_ID: "test-image:latest"
+  VERSION_CODENAME: "bookworm"
 steps:
 - name: gcr.io/cloud-builders/docker
   args: [
@@ -44,7 +45,7 @@ steps:
       # Add the repository to Apt sources:
       echo \
         "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/debian \
-        $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
+        $(. /etc/os-release && echo "${VERSION_CODENAME}") stable" | \
         sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
       apt-get -y install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
       # Install python dependencies
@@ -54,8 +55,6 @@ steps:
       pip install --require-hashes -r hermetic_build/library_generation/requirements.txt
       pip install hermetic_build/library_generation
       python -m unittest hermetic_build/library_generation/tests/integration_tests.py
-  env:
-  - "VERSION_CODENAME=bookworm"
   waitFor: ["library-generation-build"]
   id: integration-test