This is an example workflow that shows how to keep build number in a repository and keep it up-to-date. This action is fired on push to specified branch.

ExampleGitHubActionWithCommitAndPush.yaml

name: Awesome App
# Controls when the action will run. 
on:
  # Triggers the workflow on push or pull request events but only for the develop branch
  push:
    branches: [ master ]
  # pull_request:
  #   branches: [ develop ]
jobs:
  name: Build master
    runs-on: calculator
    steps:
    # steps fast overview
    # 1. We checkout on a commit
    # 2. Increment build number in a file under git tracking.
    # 3. Build an artifact
    # 4. Upload an artifact to github.
    # 5. Commit updated build number.
    # 6. Push a commit with a file with new build number to a repository.
      # Checkout commit
      - name: Checkout
        uses: actions/checkout

      # Increment build number
      - name: Increment build number
        run: |
          NUMBER=./scripts/get_build_number.sh
          NUMBER=$(NUMBER+1)
          write_build_number($NUMBER)

      # Build an artifact
      - name: Build artifact
        run: sh ./scripts/build_release.sh

      # Upload artifact
      - name: Upload artifact to git
        uses: actions/upload-artifact
        with: path-to-build

      # Commit updated build number
      - name: Additional commit of build number file
        uses: actions/commit
        message: version number $(NUMBER) # read from manifest? ok
        path: BUILD_NUMBER_FILE

      # Push updated build number
      - name: Push updated build number to repository
        run: git push