Log Message:
Add grpcurl version 1.9.1

`grpcurl` is a command-line tool that lets you interact with gRPC
servers. It's basically `curl` for gRPC servers.

The main purpose for this tool is to invoke RPC methods on a gRPC
server from the command-line. gRPC servers use a binary encoding
on the wire ([protocol
buffers](https://developers.google.com/protocol-buffers/), or
"protobufs" for short). So they are basically impossible to interact
with using regular `curl` (and older versions of `curl` that do not
support HTTP/2 are of course non-starters).  This program accepts
messages using JSON encoding, which is much more friendly for both
humans and scripts.