internal/gophers: add Carlos Amedee gomote user mapping

Add my GitHub user to the gomote user mapping.

Change-Id: Id4a783e0e624c9f1562761960cb35f923ab6934a
Reviewed-on: https://go-review.googlesource.com/c/build/+/210817
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/internal/gophers/gophers.go b/internal/gophers/gophers.go
index b90e070..2aab2a0 100644
--- a/internal/gophers/gophers.go
+++ b/internal/gophers/gophers.go
@@ -3174,6 +3174,8 @@
 // GithubOfGomoteUser returns the GitHub username for the provided gomote user.
 func GithubOfGomoteUser(gomoteUser string) (githubUser string) {
 	switch gomoteUser {
+	case "amedee":
+		return "cagedmantis"
 	case "austin":
 		return "aclements"
 	case "cbro":