fix: git setup user name should use GITLAB_CI_USER_NAME

Author: AdrielLimanthie

src/gitUtils.ts

@@ -3,7 +3,7 @@ import { exec } from '@actions/exec'
 import { execWithOutput, identify } from './utils.js'
 
 export const setupUser = async () => {
-  await exec('git', ['config', 'user.name', process.env.GITLAB_USER_NAME!])
+  await exec('git', ['config', 'user.name', process.env.GITLAB_CI_USER_NAME!])
   await exec('git', [
     'config',
     'user.email',