[github] Add keith back to bazel codeowners

Wrongly removed in 45cc6bd.

Author: tbaederr

.github/CODEOWNERS

@@ -132,7 +132,7 @@ clang/test/AST/Interp/ @tbaederr
 /bolt/ @aaupov @maksfb @rafaelauler @ayermolo @dcci
 
 # Bazel build system.
-/utils/bazel/ @rupprecht
+/utils/bazel/ @rupprecht @keith
 
 # InstallAPI and TextAPI
 /llvm/**/TextAPI/ @cyndyishida