SECURITY.md: update go versions
SECURITY.md: update go versions

Change-Id: I59446965b198767af60d617da29b5c2e457829ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/197477
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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