Bump version to 2.3.9

Bump version to 2.3.8

Bump version to 2.3.7

Bump version to 2.3.6

Bump version to 2.3.5

Bump version to 2.3.4

Bump version 2.3.3

Deploy: Add download wheel step

Bump version to 2.3.1

Update README (#1757)