[gtk/ebassi/ci-only] ci: Specify `only` for other jobs

[Emmanuele Bassi <ebassi src gnome org>]

commit d7aa76c249c04bdac06a54f2f7c2932ecf16acfd
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Jan 7 16:03:10 2021 +0000

    ci: Specify `only` for other jobs
    
    Otherwise MRs will only run macOS jobs.

 .gitlab-ci.yml | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5b5ee631a3..2a0be893f0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -43,7 +43,12 @@ style-check-diff:
     - .gitlab-ci/run-style-check-diff.sh
 
 .build-fedora-default:
+  extends: .only-default
   image: $FEDORA_IMAGE
+  only:
+    - master
+    - merge_requests
+    - branches
   artifacts:
     when: always
     reports:
@@ -121,6 +126,7 @@ installed-tests:
 
 
 .mingw-defaults:
+  extends: .only-default
   stage: build
   tags:
     - win32-ps