refactor(yaml): replace anchors with ref tags

templates/gitlab-ci-gcloud.yml

@@ -403,7 +403,7 @@ stages:
     - name: "$TBC_TRACKING_IMAGE"
       command: ["--service", "gcloud", "5.0.2" ]
   before_script:
-    - *gcp-scripts
+    - !reference [.gcp-scripts]
     - install_ca_certs "${CUSTOM_CA_CERTS:-$DEFAULT_CA_CERTS}"
     - gcp_auth