Add option to push to another branch

[Krzysztof-Cieslak]

This is kind of follow up on #2 - since in my repository master branch is protected I don't really see any way to use the GH action currently. It could be nice if I could push the diagram to another branch, and then merge it on my own if I want.

This could be also useful for folks keeping documentation on docs branch or for GH Pages hosted on gh-pages branch.

[special-character]

I ended up making mine run on every push:

name: Create diagram
on:
  workflow_dispatch: {}
  push:

jobs:
  get_data:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@master
      - name: Update diagram
        uses: githubocto/repo-visualizer@main

[RazvanDH]

I've opened a PR to allow for the branch option: #25