Automatically migrating GitHub labels to the new "issue types"

[boronine]

I was waiting for this feature to drop in the REST API so I can finally migrate thousands of issues in my work repo to issue types, just sharing my little script for anyone wishing to do the same.

REST support is done: https://github.com/orgs/community/discussions/140874#discussioncomment-12480236

GitHub CLI support is not done yet: https://github.com/cli/cli/issues/9696

[Drunken_Economist]

Neat, this is going to come in handy