e2e: Fetch the correct user name

When fetching the user name, you need to use User.Username
instead of User.Name, as with other tests.

Signed-off-by: Toshiki Sonoda <sonoda.toshiki@fujitsu.com>

test/e2e/play_kube_test.go

@@ -4533,7 +4533,7 @@ ENV OPENJ9_JAVA_OPTIONS=%q
 	It("podman play kube using a user namespace", func() {
 		u, err := user.Current()
 		Expect(err).ToNot(HaveOccurred())
-		name := u.Name
+		name := u.Username
 		if name == "root" {
 			name = "containers"
 		}