bump version to 2.2.1

update changelog with merged changes

Update to version 2.1.5

Update to version 2.1.4

Fix issue AntonKueltz#54 and update to v2.1.3

Update docs to v2.1.2

Update to v2.1.1

fix: add type validation for point arithmetic

Update docs to version 2.0.0

Version 1.7.5