net-mgmt/py-gstat_exporter: update to latest
The author has just adopted a new release numbering scheme. The new
release is "v0.2.0". Update PORTEPOCH accordingly. Also, switch
MASTER_SITES from github to pypi.
PR: 275766
Sponsored by: Axcient
Approved by: Lap Luchini <lapo@lapo.it> (maintainer), fuz (ports)