internal/gophers: update Kevin Burke's Gerrit email

Gopherbot fails to add the previous email as a reviewer because it's
not associated with any Gerrit account anymore. Update it to the one
reported by 'curl https://go-review.googlesource.com/accounts/13437'.
Also merge the two addPerson calls into one while here.

For golang/go#28320.

Change-Id: If2ee53299d9f54eb1d1d3e8609e7c92ff705f91e
Reviewed-on: https://go-review.googlesource.com/c/build/+/502855
Reviewed-by: Heschi Kreinick <[email protected]>
Run-TryBot: Dmitri Shuralyov <[email protected]>
Auto-Submit: Dmitri Shuralyov <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

Author: dmitshur

internal/gophers/gophers.go

@@ -1646,8 +1646,7 @@ func init() {
 	addPerson("Ketan Parmar", "[email protected]")
 	addPerson("Ketan Parmar", "[email protected]", "@kpbird")
 	addPerson("Kevin Ballard", "[email protected]", "@kballard")
-	addPerson("Kevin Burke", "[email protected]", "13437@62eb7196-b449-3ce5-99f1-c037f21e1705")
-	addPerson("Kevin Burke", "[email protected]", "@kevinburke")
+	addPerson("Kevin Burke", "[email protected]", "@kevinburke", "13437@62eb7196-b449-3ce5-99f1-c037f21e1705")
 	addPerson("Kevin Kirsche", "[email protected]", "@kkirsche")
 	addPerson("Kevin Klues", "[email protected]", "@klueska")
 	addPerson("Kevin Lozandier", "[email protected]")