Keep a single ci-5.x.yml file

For CI builds triggered by pushes to supported branches or pull requests, we can have a single file that lists the branches.

Signed-off-by: Thomas Segismont <tsegismont@gmail.com>

Author: tsegismont

.github/workflows/ci-5.x-stable.yml

@@ -3,9 +3,11 @@ on:
   push:
     branches:
       - master
+      - '5.[0-9]+'
   pull_request:
     branches:
       - master
+      - '5.[0-9]+'
 jobs:
   CI-CD:
     uses: ./.github/workflows/ci-matrix-5.x.yml