ci(gcb): Fix GCB failures due to missing extra $$ (#21370)

This is a follow up to #21360 as it failed to address the underlying issue. GCB uses the `$xxx` syntax for variable expansion and it opreates in 'loose' mode when a trigger runs the build. This means it simply replaces unknown substitions with empty strings. This collides with how we try to use env variables which has the same syntax so the need to use `$$` syntax for GCB to not replace them with empty strings.

docker/cloudbuild.yaml

@@ -64,8 +64,6 @@ steps:
       - get-onpremise-repo
     entrypoint: 'bash'
     dir: onpremise
-    env:
-      - 'SENTRY_IMAGE=us.gcr.io/$PROJECT_ID/sentry:$COMMIT_SHA'
     args:
       - '-e'
       - '-c'
@@ -91,7 +89,6 @@ steps:
     entrypoint: 'bash'
     dir: onpremise
     env:
-      - 'SENTRY_IMAGE=us.gcr.io/$PROJECT_ID/sentry:$COMMIT_SHA'
       - 'SENTRY_PYTHON3=1'
     args:
       - '-e'
@@ -115,8 +112,6 @@ steps:
       - e2e-test-py2
     secretEnv: ['DOCKER_PASSWORD']
     entrypoint: 'bash'
-    env:
-      - 'SENTRY_IMAGE=us.gcr.io/$PROJECT_ID/sentry:$COMMIT_SHA'
     args:
       - '-e'
       - '-c'
@@ -124,22 +119,20 @@ steps:
         # Only push to Docker Hub from master
         [ "$BRANCH_NAME" != "master" ] && exit 0
         # Need to pull the image first due to Kaniko
-        docker pull $SENTRY_IMAGE
+        docker pull $$SENTRY_IMAGE
         echo "$$DOCKER_PASSWORD" | docker login --username=sentrybuilder --password-stdin
-        docker $SENTRY_IMAGE $DOCKER_REPO:$SHORT_SHA
-        docker push $DOCKER_REPO:$SHORT_SHA
-        docker $SENTRY_IMAGE $DOCKER_REPO:$COMMIT_SHA
-        docker push $DOCKER_REPO:$COMMIT_SHA
-        docker $SENTRY_IMAGE $DOCKER_REPO:nightly
-        docker push $DOCKER_REPO:nightly
+        docker $$SENTRY_IMAGE $$DOCKER_REPO:$SHORT_SHA
+        docker push $$DOCKER_REPO:$SHORT_SHA
+        docker $$SENTRY_IMAGE $$DOCKER_REPO:$COMMIT_SHA
+        docker push $$DOCKER_REPO:$COMMIT_SHA
+        docker $$SENTRY_IMAGE $$DOCKER_REPO:nightly
+        docker push $$DOCKER_REPO:nightly
   - name: 'gcr.io/cloud-builders/docker'
     id: docker-push-py3
     waitFor:
       - e2e-test-py3
     secretEnv: ['DOCKER_PASSWORD']
     entrypoint: 'bash'
-    env:
-      - 'SENTRY_IMAGE=us.gcr.io/$PROJECT_ID/sentry:$COMMIT_SHA'
     args:
       - '-e'
       - '-c'
@@ -147,14 +140,14 @@ steps:
         # Only push to Docker Hub from master
         [ "$BRANCH_NAME" != "master" ] && exit 0
         # Need to pull the image first due to Kaniko
-        docker pull $SENTRY_IMAGE-py3
+        docker pull $$SENTRY_IMAGE-py3
         echo "$$DOCKER_PASSWORD" | docker login --username=sentrybuilder --password-stdin
-        docker $SENTRY_IMAGE-py3 $DOCKER_REPO:$SHORT_SHA-py3
-        docker push $DOCKER_REPO:$SHORT_SHA-py3
-        docker $SENTRY_IMAGE-py3 $DOCKER_REPO:$COMMIT_SHA-py3
-        docker push $DOCKER_REPO:$COMMIT_SHA-py3
-        docker $SENTRY_IMAGE-py3 $DOCKER_REPO:nightly-py3
-        docker push $DOCKER_REPO:nightly-py3
+        docker $$SENTRY_IMAGE-py3 $$DOCKER_REPO:$SHORT_SHA-py3
+        docker push $$DOCKER_REPO:$SHORT_SHA-py3
+        docker $$SENTRY_IMAGE-py3 $$DOCKER_REPO:$COMMIT_SHA-py3
+        docker push $$DOCKER_REPO:$COMMIT_SHA-py3
+        docker $$SENTRY_IMAGE-py3 $$DOCKER_REPO:nightly-py3
+        docker push $$DOCKER_REPO:nightly-py3
   - name: 'node:12'
     id: zeus-upload
     waitFor:
@@ -167,14 +160,14 @@ steps:
       - |
         # Only push to Zeus from releases/*
         [[ ! "$BRANCH_NAME" =~ ^releases/ ]] && exit 0
-        npx -p "@zeus-ci/cli" zeus job update --build $BUILD_ID --job 1 --ref $COMMIT_SHA --build-label GCB --job-label "OSS Packages"
-        npx -p "@zeus-ci/cli" zeus upload --build $BUILD_ID --job 1 --type "application/x-pywheel+zip" dist/*.whl
         npx -p "@zeus-ci/cli" zeus job update --build $BUILD_ID --job 1 --ref $COMMIT_SHA --build-label GCB --job-label "OSS Packages" --status passed
+        npx -p "@zeus-ci/cli" zeus upload --build $BUILD_ID --job 1 --type "application/x-pywheel+zip" dist/*.whl
 timeout: 2400s
 options:
   # We need more memory for Webpack builds & e2e onpremise tests
   machineType: 'N1_HIGHCPU_8'
   env:
+    - 'SENTRY_IMAGE=us.gcr.io/$PROJECT_ID/sentry:$COMMIT_SHA'
     - 'DOCKER_REPO=getsentry/sentry'
     - 'SENTRY_TEST_HOST=http://nginx'
     - 'CI=1'