Update ubuntu

Avoid partial functions

Update upper bounds

2023

Document the main types

base 4.17

Add note about key deduplication

Add haskell-ci

Update copyright and bug-reports fields

Add Data.BimapMany simple variant

without any extra values

Move BimapMany to BimapMany.Extended

in preparation to
* extending BimapMany.Extended
* creating a regular variant with no extra values

Split utils into internal module

Add test for stray empty sets

Add reference to bimap

gitignore cabal.project.local~

Fix typos

Add elems* and keys* functions

ghc 9.2

Lazy/strict Functor and Traversable instances

Cabal file improvements