release v3.3.1 (katspaugh#1848)

* update changelog

* bump version: 3.3.1

release v3.3.0 (katspaugh#1835)

* update dev dependencies

* bump version: 3.3.0

* update copyright year

release: v3.2.0 (katspaugh#1783)

* bump version: 3.2.0

* fix notation

bump version: 3.1.0

release 3.0.0 (katspaugh#1688)

* bump version: 3.0.0

* doc update

bump version: 2.2.1 (katspaugh#1598)

release 2.2.0 (katspaugh#1582)

* bump version: 2.2.0

* doc: remove duplicate badges

Release 2.1.3 (katspaugh#1558)

* update dev dependencies

* bump version: 2.1.3

* add favicon

* update date

* update dev dependencies

Release 2.1.2 (katspaugh#1545)

* update changelog

* bump version

* bump version

* add upgrade document

* add UPGRADE doc reference

* bump date

* happy new year

bump version: 2.1.1 (katspaugh#1512)