github: Set the correct permissions on repos for teams

[issyl0]

• I can't figure out the imports (my brain is melting).

[issyl0]

I don't have time for this right now, sorry.

[SMillerDev]

Meaning to pick this up later. In the meantime, what do you think of the format with hypothetical permissions:

core = {
  "homebrew-core" = "maintain"
}
ops = {
  "homebrew-core" = "read"
  "homebrew-cask" = "read"
}