rust_tools: add a monitor for upstream gentoo commits + rust releases

Apparently it's useful to watch upstream Gentoo's patches to
dev-lang/rust, and it'd be nice in general if we were pinged for new
Rust stable releases.

This CL adds a tool to handle the alerting of all of that for us.

BUG=None
TEST=Ran in a few different ways with `--skip_email`

Change-Id: Ie972872d597870c715266f88df50812b55e30c75
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2314745
Reviewed-by: Tiancong Wang <tcwang@google.com>
Tested-by: George Burgess <gbiv@chromium.org>
2 files changed