• Add explicit dependency on security/py-service_identity
• Switch to USE_GITHUB and the GH_* foo
• Update WWW in pkg-descr
• Bump PORTREVISION

While I'm here, pet portlint, CATEGORIES appears out-of-order and USE_* comes
before USES.

PR: 221940
Submitted by: xmj
Approved by: rm (maintainer timeout, 2 weeks)