Add maintainer affiliations

[rgdd]

Add affiliations in list of maintainers (was not added in 1st iteration because rgdd wasn't sure what everyone wanted to put down).

[rgdd]

I'd like to put down "Rasmus Dahlberg (Glasklar Teknik)". I could also put Sigsum, or both Sigsum and Glasklar if anyone thinks that is helpful. Let me know!

What do you want to put down @AlCutter, @FiloSottile?