Add Descriptive Error Message to Upgrade Command (#752)

* Add Descriptive Error Message to Upgrade Command

* Reword Error Message

Author: farisj

cmd/upgrade.go

@@ -23,7 +23,18 @@ You can always delete this file.
 	`,
 	RunE: func(cmd *cobra.Command, args []string) error {
 		c := cli.New(Version)
-		return updateCLI(c)
+		err := updateCLI(c)
+		if err != nil {
+			return fmt.Errorf(`
+
+We were not able to upgrade the cli because we encountered an error:
+%s
+
+Please check the FAQ for solutions to common upgrading issues.
+
+https://exercism.io/faqs`, err)
+		}
+		return nil
 	},
 }