[feature request] Implement `create_branch`/`delete_branch` action

[abhishek-j16]

Would be nice to have a create/delete branch action for the sake of completeness of Github actions.

For instance, if the user wants to create an automated pull request, here's how the flow would look like:

1. create branch => 2. update/create file => 3. create pull request => 4. merge pull request => 5. delete branch post merge(this can be autoconfigured as well in the settings section)

Currently. actions are implemented and available to perform step 2,3 and 4. Implementing actions for step 1 and 5 would help bring completeness to such use cases.

I'd be willing to send a PR for the same :)