Run CI on zkbesu branch and PR against it

Signed-off-by: Fabio Di Fabio <fabio.difabio@consensys.net>

.github/workflows/gradle-wrapper-validation.yml

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 name: "Validate Gradle Wrapper"
-on: [push, pull_request]
+on: [push]
 
 jobs:
   validation:

.github/workflows/workflow.yaml

@@ -3,8 +3,10 @@ name: CI
 on:
   push:
     branches:
-      - main
+      - zkbesu
   pull_request:
+    branches:
+      - zkbesu
 
 jobs:
   all: