upb-20190910-bp154.1.32

- Use native.bazel_version function instead of @bazel_version
  package.

- Add source package

- Initial release
- Add patches which make upb able to build on OBS:
  * 0001-cmake-Add-descriptor_upbproto-library-for-shared-lin.patch
  * 0002-cmake-Add-upb_-prefix-to-libraries-which-can-be-shar.patch
  * 0003-cmake-Add-SOVERSION-to-shared-libraries.patch
  * 0004-cmake-Add-support-for-installation.patch
  * 0005-Do-not-build-tests.patch