updated GitHub actions workflows to include branch 20.0

Author: TomasLudvik

.github/workflows/rebuild-dev-image.yaml

@@ -9,7 +9,7 @@ jobs:
         runs-on: ubuntu-22.04
         strategy:
             matrix:
-                branches: ['14.0', '14.5', '18.0', '19.0']
+                branches: ['14.0', '14.5', '18.0', '19.0', '20.0']
             fail-fast: false
         permissions:
             contents: read