Uncomment upgrade code to 4.8 (#8409)

* upgrade to 48

* fix upgrade bug

store/sqlstore/upgrade.go

@@ -365,8 +365,7 @@ func UpgradeDatabaseToVersion471(sqlStore SqlStore) {
 }
 
 func UpgradeDatabaseToVersion48(sqlStore SqlStore) {
-	//TODO: Uncomment the following condition when version 4.8.0 is released
-	//if shouldPerformUpgrade(sqlStore, VERSION_4_7_0, VERSION_4_8_0) {
-	//	saveSchemaVersion(sqlStore, VERSION_4_8_0)
-	//}
+	if shouldPerformUpgrade(sqlStore, VERSION_4_7_1, VERSION_4_8_0) {
+		saveSchemaVersion(sqlStore, VERSION_4_8_0)
+	}
 }