www/threema-web: update 2.5.0 to 2.5.2

  CHANGELOG;

    * https://github.com/threema-ch/threema-web/blob/master/CHANGELOG.md

    [feature] Add support for Threema Gatway push service (#1175)
    [bug] Fix file size limit check (#1179)
    [change] Upgrade many dependencies
    [feature] Show group reaction names on hover (#1164)
    [change] Upgrade dependencies

  DIFF;

    * https://github.com/threema-ch/threema-web/compare/v2.5.0...v2.5.2

  Q/A;

    * poudriere/testport OK for 12, 13 and 14;
    * while here, pet portlint;
    * updated WWW on Makefile to reflect the app's code repository;
    * fix a mix of b7f05445 and fb16dfec.

PR:		274808
Reported by:	Ralf van der Enden <tremere % cainites.net>