Restrict trigger push branch for GitHub Workflow (#1619)

Feature branches rarely need their own CI runs: the code is already
tested when a pull request is opened against a release branch. If the
push trigger has no branch restriction and pull_request is also
configured, every push to a branch with an open PR runs the workflow
twice: once for the push and once for the PR synchronisation.

Always give the push trigger an explicit list of branches: this stops
branches created from a release branch from inheriting its workflow
runs.

see https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=430408443#GitHubActionsRecommendedPractices-Restrictthepushtriggertospecificbranches

Signed-off-by: Aurélien Pupier <apupier@ibm.com>

Author: apupier

.github/workflows/dev.yml

@@ -16,7 +16,12 @@
 # under the License.
 
 name: Dev
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - main
+      - branch-*
+  pull_request:
 
 jobs: