* New upstream stable release (79.0+build1)

[ Rico Tzschichholz ]
* Require python >= 3.6
  - debian/control{,.in}
* Update patches
  - debian/patches/fix-armhf-webrtc-build.patch
  - debian/patches/unity-menubar.patch
* Bump build-dep on rustc >= 1.43.0 and cargo >= 0.44
  - debian/control{,.in}
* Drop unnecessary patch to cleanup old distributions (LP: #1885903)
  - debian/patches/cleanup-old-distribution-search-engines.patch