CONTRIBUTORS: update for the Go 1.18 release

This update was created using the updatecontrib command:

	go install golang.org/x/build/cmd/updatecontrib@latest
	cd gotip
	updatecontrib

With manual changes based on publicly available information
to canonicalize letter case and formatting for a few names.

For golang#12042.

Change-Id: If08b7e798cff6ec4248011bdadcc524b510aaff7
Reviewed-on: https://go-review.googlesource.com/c/go/+/388394
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Trust: Carlos Amedee <carlos@golang.org>