workflows: enable build-on-push in next branch

Replicate build on push in the next branch. This will help testing the
workflow changes.

Signed-off-by: Milosz Wasilewski <milosz.wasilewski@oss.qualcomm.com>

Author: mwasilew

.github/workflows/push.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - master
+      - next
 
 permissions:
   checks: write