Merge branch 'ps/ci-gitlab-upgrade'

CI updates.

* ps/ci-gitlab-upgrade:
  gitlab-ci: upgrade machine type of Linux runners

Author: gitster

.gitlab-ci.yml

@@ -9,6 +9,8 @@ workflow:
 
 test:linux:
   image: $image
+  tags:
+    - saas-linux-medium-amd64
   variables:
     CUSTOM_PATH: "/custom"
   before_script: