package/python-distro: bump to version 1.7.0

For change log since 1.6.0, see:
- https://github.com/python-distro/distro/releases/tag/v1.7.0



Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>