[mutter/alatiera/workflow-rules] wip: migrate to rules to avoid double pipelines

[Jordan Petridis <jpetridis src gnome org>]

commit 36f5b36217b0ffc0e75eaac22d56c92dd3f2fede
Author: Jordan Petridis <jpetridis gnome org>
Date:   Thu Nov 19 16:59:01 2020 +0200

    wip: migrate to rules to avoid double pipelines

 .gitlab-ci.yml | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d2a424c75d..5eafd4d6d3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -30,10 +30,19 @@ stages:
 
       dnf clean all
 
+workflow:
+  rules:
+    - if: '$CI_MERGE_REQUEST_IID'
+    - if: '$CI_COMMIT_TAG'
+    - if: '$CI_COMMIT_BRANCH'
+
 .only_default: &only_default
-  only:
-      - merge_requests
-      - /^.*$/
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+    - if: '$CI_COMMIT_TAG'
+    - if: '$CI_COMMIT_BRANCH == "$CI_DEFAULT_BRANCH"'
+    - if: '$CI_COMMIT_BRANCH =~ /^gnome-[0-9-]\+$/'
+    - when: 'manual'
 
 build-fedora-container:
   extends: