Re: [PATCH v2 5/5] gitlab-ci: add whitespace error check

GitLab CI does not have a job to check for whitespace errors introduced
by a set of changes. Reuse the existing generic `whitespace-check.sh` to
create the job for GitLab pipelines.

Note that the `$CI_MERGE_REQUEST_TARGET_BRANCH_SHA` variable is only
available in GitLab merge request pipelines and therefore the CI job is
configured to only run as part of those pipelines.

Signed-off-by: Justin Tobler <redacted>
---
 .gitlab-ci.yml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index c0fa2fe90b..6d046ce409 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml

@@ -102,3 +102,12 @@ static-analysis:
   script:
     - ./ci/run-static-analysis.sh
     - ./ci/check-directional-formatting.bash
+
+check-whitespace:
+  image: ubuntu:latest
+  before_script:
+    - ./ci/install-docker-dependencies.sh
+  script:
+    - ./ci/check-whitespace.sh "$CI_MERGE_REQUEST_TARGET_BRANCH_SHA"
+  rules:
+    - if: $CI_PIPELINE_SOURCE == 'merge_request_event'