CONTRIBUTORS: update for the Go 1.16 release
CONTRIBUTORS: update for the Go 1.16 release

This update was created using the updatecontrib command:

	go get golang.org/x/build/cmd/updatecontrib
	cd gotip
	updatecontrib

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

For #12042.

Change-Id: I030b77e8ebcc7fe02106f0f264acdfb0b56e20d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/291189
Trust: Carlos Amedee <ab5e2bca84933118bbc9d48ffaccce3bac4eeb64@golang.org>
Run-TryBot: Carlos Amedee <ab5e2bca84933118bbc9d48ffaccce3bac4eeb64@golang.org>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Reviewed-by: Alexander Rakoczy <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@golang.org>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>

CAFxX/go,cloudflare/go,golang/go,golang/go,golang/go,nawawi/go,nawawi/go,nawawi/go,golang/go,CAFxX/go,nawawi/go,CAFxX/go,cloudflare/go,CAFxX/go,cloudflare/go,CAFxX/go,golang/go,cloudflare/go,CAFxX/go,nawawi/go,cloudflare/go,nawawi/go,golang/go,CAFxX/go,golang/go,nawawi/go,golang/go,cloudflare/go,nawawi/go,CAFxX/go,cloudflare/go,cloudflare/go