audio/id3mtag: update to 0.81

Changes in id3 0.81:

• Will now also update ID3v2 tags by default (if they are present)
• Add support for POPM frames
• Fixes bugs (thanks geeknik!)
• Replaces code removed by C++17 to fix compilation issues in FreeBSD 14

Changes in the package:

• maintainer email address changed (the old one still works for now)
• bash-completion files are now installed unconditionally
• bash-completion files are now installed into the right places

PR: 272410