* New upstream release from the beta channel (FIREFOX_69_0b4_BUILD2)
* Bump build-dep to clang-8 and llvm-8-dev
  - debian/config/mozconfig.in
  - debian/control{,.in}
* Update patches
  - debian/patches/ubuntu-ua-string-changes.patch
* Update cbindgen to 0.9.0
  - debian/build/create-tarball.py
* Pass --with-clang-path=... --with-libclang-path=... accordingly
  - debian/config/mozconfig.in
* Bump build-dep on rustc >= 1.35.0 and cargo >= 0.36
  - debian/control{,.in}
* Drop upstreamed patches
  - debian/patches/skcms-workaround-gcc-bug.patch