databases/py-apsw: update to 3.13.0-r1

• Update PORTVERSION, adjust distinfo
• Add LICENSE_FILE entry
• Fix WWW in pkg-descr
• Add UPDATING entry, per potential backwards incompatibility listed for 3.12.2-r1 we're jumping over.

While I'm here, remove unneded PYDISTUTILS_EGGINFO knob.

PR: 210376
Submitted by: Vladimir Krstulja <vlad-fbsd@acheronmedia.com>