message: Update zlib package from 1.2.11 to 1.2.12
  The previous version is no longer available for download and breaks
  builds.
diff: @@ -125,9 +125,9 @@ http_archive(
  http_archive(
  name = "net_zlib",
  build_file = "@com_google_protobuf//:third_party/zlib.BUILD",
  - sha256 = "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1",
  - strip_prefix = "zlib-1.2.11",
  - urls = ["https://zlib.net/zlib-1.2.11.tar.gz"],
  + sha256 = "91844808532e5ce316b3c010929493c0244f3d37593afd6de04f71821d5136d9",
  + strip_prefix = "zlib-1.2.12",
  + urls = ["https://zlib.net/zlib-1.2.12.tar.gz"],
  )
  http_archive(
  