Feature request: return the number of the PR created as an output

[xiehan]

From what I can tell, this is already available in the code, so it should hopefully be fairly easy to return it as an output.

github-actions-version-updater/src/main.py

Line 79 in a7fd643

pull_request_number = create_pull_request(

How to specify that an Action has outputs: https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#outputs-for-docker-container-and-javascript-actions
End-to-end example including how to set the output: https://docs.github.com/en/actions/creating-actions/creating-a-docker-container-action

Use case: I have a process that needs to run on the PR that was created by this action. Right now I do:

prnumber=$(gh search prs --repo ${{ github.repository }} --state open --match title "$PR_TITLE" --json number --jq '.[].number')

... which works but is kinda janky. It'd be great if this action would just return the number of the PR that was created so I wouldn't have to do this extra step.