Reformat long line and quote around variable expansion

Quotes required for correct operation if there are spaces or some other
shell-special characters

.gitlab-ci.yml

@@ -74,7 +74,13 @@ system-tests:
 .update-grid: &UPDATE_GRID
   stage: "deploy"
   script: |
-    env --ignore-environment - NIX_PATH=$NIX_PATH GITLAB_USER_LOGIN=$GITLAB_USER_LOGIN CI_JOB_NAME=$CI_JOB_NAME CI_PIPELINE_SOURCE=$CI_PIPELINE_SOURCE CI_COMMIT_BRANCH=$CI_COMMIT_BRANCH ./ci-tools/update-grid-servers "${PRIVATESTORAGEIO_SSH_DEPLOY_KEY_PATH}" "${CI_ENVIRONMENT_NAME}"
+    env --ignore-environment - \
+      NIX_PATH="$NIX_PATH" \
+      GITLAB_USER_LOGIN="$GITLAB_USER_LOGIN" \
+      CI_JOB_NAME="$CI_JOB_NAME" \
+      CI_PIPELINE_SOURCE="$CI_PIPELINE_SOURCE" \
+      CI_COMMIT_BRANCH="$CI_COMMIT_BRANCH" \
+      ./ci-tools/update-grid-servers "${PRIVATESTORAGEIO_SSH_DEPLOY_KEY_PATH}" "${CI_ENVIRONMENT_NAME}"
 
 # Update the staging deployment - only on a merge to the staging branch.
 update-staging: