www/py-seafobj: update 5.1.6 -> 6.0.3

This version has no commits between the two, but I want to keep
seafdav and seafobj the same version for sanity.

• Updated to 6.0.3
• Added license file
• Fixed pkg-desc www --> WWW

PR: 214656
Submitted by: Ultima1252@gmail.com (maintainer)