v0.15

New Features

• Add support for Python 3.10 and more tests
  (by @vstinner in 45105ec for #46, @hukkinj1 in d7f3eeb, f0b4fd4)

• Make __repr__ more similar to other mapping types
  (by @ofek in 8af1502 for #17)

Misc

• Minor docs and CI fixes
  (by @MisterKeefe in 76e491c for #32, @fantix in 1282379 for #39)