check_branch_name.yml

name: Check branch name
on:
  push:
    branches:
      - main
  pull_request_target:
    types: [opened, synchronize, reopened]
jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - name: Get branch names
        id: branch-name
        uses: tj-actions/branch-names@v7
      - name: Current branch name
        if: ${{steps.branch-name.outputs.current_branch == 'main'}}
        uses: actions/github-script@v3
        with:
         script: |
          core.setFailed('Branch shouldn't be main')