Update changelog

Release 2.8.0 (#3360)

Release 2.7.0 (#3323)

Releasing v2.6.1 (#3230)

Fix PyPi upload (#3200)

Fix according to pypa/twine#1216.

Release v2.5.0 (#3079)

Release v2.4.0 (#3027)

Release v2.3.0 (#2926)

Release v2.2.0 (#2886)

Release 2.1.1 (#2777)