Update Maven workflow to remove push trigger

Removed push trigger for specific branches in Maven workflow.

Signed-off-by: Ryan Baxter <ryan.baxter@broadcom.com>

Author: ryanjbaxter

.github/workflows/maven.yml

@@ -4,8 +4,6 @@
 name: Build
 
 on:
-  push:
-    branches: [ main, 4.3.x, 4.2.x, 4.1.x ]
   pull_request:
     branches: [ main, 4.3.x, 4.2.x, 4.1.x ]