Chore: prepare for 3.8.1 release (optimizely#329)

* chore: prepare for 3.8.1 release

* fix: version 3.9.0

* fix: update date

chore: Preparing for 3.8.0 release (optimizely#315)

* feat(release) bump version, update changelog, update py version

* updtae changelog note

* again updtae changelog note

chore: Release 3.7.1 (optimizely#308)

Preparing for 3.7.0 release (optimizely#304)

chore: Preparing for 3.6.0 release (optimizely#301)

chore(release): Preparing for 3.5.2 release (optimizely#290)

chore(release): Preparing for 3.5.1 release (optimizely#286)

chore(release): Preparing for 3.5.0 release (optimizely#281)

chore(release): Update version

chore(release): Release 3.4.1 (optimizely#241)