Branch 1.5 reached EOL
Merge branch '1.5' into 1.6
Branch 1.6 is in maintenance mode
Merge branch '1.6' into 1.7
Remove outdated TODO item

Python 3 support is being developed in branch 3.0.

[skip ci]
Merge branch '1.6' into 1.7

Python 3 support is being developed in branch 3.0.

[skip ci]
Merge branch '1.7' into 2.0

Python 3 support is being developed in branch 3.0.

[skip ci]