ci: add master back to workflow triggers

Github needs to see all the triggers on the master branch version of this file
for them to work. We should keep the same triggers on the release branch.

Signed-off-by: Christian Hopps <[email protected]>

Author: choppsv1

.github/workflows/ci.yml

@@ -6,9 +6,11 @@ name: CI
 on:
   pull_request:
     branches:
+      - master
       - b_3.x
   push:
     branches:
+      - master
       - b_3.x
     tags:
       - v*