Ensure that we can push with environment tag is specified

Author: micjustus-nc

.github/workflows/stage-3-build.yaml

@@ -148,6 +148,7 @@ jobs:
         run: |
           docker compose -f ${COMPOSE_FILE//,/ -f } -p ${PROJECT_NAME} build --no-cache --pull ${{ matrix.function }}
           docker tag ${IMAGE_NAME}:latest "${REPO_PATH}:${PR_NUM_TAG}"
+          [[ -n "${ENVIRONMENT_TAG}" ]] && docker tag "${IMAGE_NAME}:latest "${REPO_PATH}:${ENVIRONMENT_TAG}"
 
       - name: AzureCLI login
         if: github.ref == 'refs/heads/main' && env.USE_AZURECR == 'true'