Re-enable upgrade NFR test (#3482)

Problem: Due to the 2.0 architectural change, the upgrade test needed to be disabled.

Solution: Re-enable this test now that upgrades work again post-2.0.

Author: sjberman

tests/suite/upgrade_test.go

@@ -92,7 +92,6 @@ var _ = Describe("Upgrade testing", Label("nfr", "upgrade"), func() {
 	})
 
 	It("upgrades NGF with zero downtime", func() {
-		Skip("Skipping test until version 2.1.0 since 2.0.0 is a breaking change")
 		nginxImage := *nginxImageRepository
 		if *plusEnabled {
 			nginxImage = *nginxPlusImageRepository