repo to run background admin migrations of conda-forge feedstocks

1. Write a subclass of admin_migrations.base.Migrator. You will need to fill out the migrate method. This method is called with the feedstock as the current working directory.
2. Add your migration class to the list in admin_migrations.__main__.main

GitHub actions is set to run once an hour on a cron job.

1. Don't migrate more than several hundred feedstocks per hour.
2. Make sure to put [ci skip] [skip ci] [cf admin skip] ***NO_CI*** in any commits to avoid massive rebuilds.
3. Rate-limit commits to feedstocks to in order to reduce the load on our admin webservices.
4. Test your migration first. The https://github.com/conda-forge/cf-autotick-bot-test-package-feedstock is available to help test migrations.
5. GitHub actions has a GITHUB_TOKEN in the environment. Please do not exhaust this token's API requests.
6. Do not rerender feedstocks!

Items 1-3 are taken care of by the migrations code.