Docs: Add instructions for required Actions settings

[penx]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the issue has not already been raised

Issue

During setup I received

Error: Unprocessable Entity: "GitHub Actions is not permitted to approve pull requests."

This is easily solved by checking "Allow GitHub Actions to create and approve pull requests" in Settings > Actions > General, but this isn't currently mentioned in the docs.

[simoneb]

Thanks for reporting this. Would you like to send a PR to document this requirement?

[simoneb]

I wonder though, the token in the workflow is required to have certain permissions, as described in the docs. It looks like these permissions are no longer enough to approve pull requests. https://github.com/fastify/github-action-merge-dependabot#usage

[penx]

Setting permissions in the workflow yaml and checking this setting was enough for me to get it working on a new rep. I didn’t need to create a new token. I think the current docs infer this but just don’t mention the setting.

[penx]

I can send a PR but won’t be today so I may need reminding 😄 actually may have 10 mins now

[penx]

Using it here if you need to reference.

https://github.com/penx/remix-google-cloud-functions/