Delete `node_modules` on push to the default branch

delete-node-modules.yml

name: Delete node_modules on merge

on:
  push:
    branches:
      - [ $default-branch ]
jobs:
  delete-modules:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v1
    - name: Use Node.js 14.x
      uses: actions/setup-node@v1
      with:
        node-version: 14.x
    - run: npm run pr:delete 

pacakge.json

{
  "name": "some package",
  "scripts": {
    "pr:delete": "rm -rf ./node_modules"

  }
}