net-im/tox: Update 0.2.20 => 0.2.21, take maitainership

Changelog:
https://github.com/TokTok/c-toxcore/releases/tag/v0.2.21

While here fix warnings from portclippy.

PR: 290838
Co-authored-by: Eric Camachat <eric@camachat.org>
MFH: 2025Q4
(cherry picked from commit 20d9bb64cd15a73a54846b0b1f01a50adfd5c79c)