Update official mail address of Zapp
The mail address changed (see source code: https://github.com/mediathekview/zapp/commit/f324c4b2308f66cb020d1b5de44cd26dfdfd68d2)
The mail address changed (see source code: https://github.com/mediathekview/zapp/commit/f324c4b2308f66cb020d1b5de44cd26dfdfd68d2)