message: update bazel readme for clang-format-8 on mac
diff: @@ -50,9 +50,9 @@ for how to update or override dependencies.
  On macOS, you'll need to install several dependencies. This can be accomplished via [Homebrew](https://brew.sh/):
  ```
  - brew install coreutils wget cmake libtool go bazel automake ninja llvm@7 autoconf aspell
  + brew install coreutils wget cmake libtool go bazel automake ninja clang-format autoconf aspell
  ```
  - _notes_: `coreutils` is used for `realpath`, `gmd5sum` and `gsha256sum`; `llvm@7` is used for `clang-format`
  + _notes_: `coreutils` is used for `realpath`, `gmd5sum` and `gsha256sum`
  Envoy compiles and passes tests with the version of clang installed by XCode 9.3.0:
  Apple LLVM version 9.1.0 (clang-902.0.30).
  