games/anki: Add pkg-message with installation instructions

• Improve the user experience by adding a pkg-message which gives some advice that audio/lame needs to be installed manually afterwards when installing from the official FreeBSD package repositories.

• Bump PORTREVISION to include the pkg-message.

PR: 242528
Submitted by: PauAmma <pauamma@gundo.com> (based on)
MFH: 2019Q4