devel/py-pyasn1-modules: update to 0.3.0

- update to 0.3.0
- switch to pep517
- update homepage link

Original author of pysnmp1 Ilya Etingof has passed away:
https://github.com/etingof/pyasn1-modules/issues/154

and all pysnmp related project were moved community-driven one.

PR:		272561
Reported by:	Alastair Hogge <agh@riseup.net>