Drop support for Python 3.7 and introduce 3.10
Drop support for Python 3.7 and introduce 3.10

NumPy's latest version does not exist for 3.7, which breaks our builds. The next version of Exdir should therefore drop support for 3.7 as well and rather introduce support for 3.10.
CINPLA/exdir,CINPLA/exdir,CINPLA/exdir