Fix annotations for PR, Prettier, and more

[andershagbard]

This PR has a few changes

src/addAnnotations.ts

• Make the sha the sha for the PR, and not the commit. This makes the annotations show up in "Files changed"
• Made sure the annotation.path is relative to GitHub, and not the --path value
• Made type GitHubAnnotation come from rest endpoint
• Removed redundant as Type in various places
• Made some functions more readable, and placed them "correctly"
• Use spread for ...ctx.repo

General

• Updated all packages to latest compatible versions
• Added prettier and ran prettier

[andershagbard]

We may also consider marking the job as completed and succeeded if using a token, as annotations will show up as an error.

Ignore the jobs in the middle, this is mixed with my other actions.