[gnome-games/wip/exalm/lint] ci: Lint with vala-lint

[Alexander Mikhaylenko <alexm src gnome org>]

commit ce8c14fab8e386969e08c4c361b155c611dd2543
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Jan 28 20:27:18 2020 +0500

    ci: Lint with vala-lint

 .gitlab-ci.yml | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index e0ffa4aa..67fc6fc7 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,6 +1,7 @@
 include: 'https://gitlab.gnome.org/GNOME/citemplates/raw/master/flatpak/flatpak_ci_initiative.yml'
 
 stages:
+  - lint
   - test
   - deploy
 
@@ -39,3 +40,9 @@ stop_review:
 
 nightly:
   extends: '.publish_nightly'
+
+lint:
+  image: valalang/lint:latest
+  stage: .pre
+  script:
+    - io.elementary.vala-lint src plugins