Integrate gRPC Starlark changes to keep Envoy working with Bazel 1.0 #7863
Description
Bazel 1.0 will remove the legacy .proto. provider to access information about protocol buffers and only allow[ProtoInfo].
These got fixed in gRPC in ecf04ccf4d8be9378166ec9e0ccf44081e211d11 and 49f0fb9035120d0f5b5fa49846324c0b2d59c257, but gRPC needs to be updated in Envoy so that they take effect.
In the meantime, I sent out grpc/grpc#19860 as a workaround.
Note that this issue has a sister issue #7835, which deals with a slightly changed directory layout in 0.29 (however, that one is breakage in Bazel 0.29 and this one is breakage in Bazel 1.0)