[gdk-pixbuf/ebassi/ci-only-default] ci: Use `only` clauses everywhere

[Emmanuele Bassi <ebassi src gnome org>]

commit 76cc030b177d4d6de23841ecf7733658ea6094d7
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Jan 12 12:31:47 2021 +0000

    ci: Use `only` clauses everywhere
    
    Otherwise GitLab will detach jobs from the pipeline.
    
    To limit the amount of work done by the macOS job, we run the build only
    on branches on the project repository.

 .gitlab-ci.yml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ec1d34663..7e1c7febd 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -19,6 +19,7 @@ variables:
     - tags
 
 .build-linux:
+  extends: .only-default
   before_script:
     - mkdir -p _ccache
   script:
@@ -57,8 +58,9 @@ macos:
   stage: build
   needs: []
   only:
-    - master
-    - merge_requests
+    - branches@GNOME/gdk-pixbuf
+  except:
+    - tags
   tags:
     - macos
   before_script: