chore: v0.5.2 release (#17)

fix: include .formatter.exs in package (again) (#15)

* fix: include .formatter.exs in package (again)

Accidentally left it out in the 0.5.0 release, breaking
custom formatting for anyone who has upgraded already.

* docs: update CHANGELOG with PR link

docs: update README with latest version

fix: don't set a `false` value param to `nil` on `new/1` (#4)

* fix: don't set a `false`-value param to `nil` on `new/1`

* chore: bump version to 0.4.1