refactor: centralise app name validation

cli/app/version.go

@@ -1,7 +1,6 @@
 package app
 
 import (
-	"errors"
 	"fmt"
 	"sort"
 	"strings"
@@ -46,10 +45,8 @@ var appVersionCommand = &cli.Command{
 	Aliases: []string{"v"},
 	Usage:   "Show version of all services in app",
 	Action: func(c *cli.Context) error {
-		appName := c.Args().First()
-		if appName == "" {
-			internal.ShowSubcommandHelpAndError(c, errors.New("no app name provided"))
-		}
+		appName := internal.ValidateAppNameArg(c)
+
 		appFiles, err := config.LoadAppFiles("")
 		if err != nil {
 			logrus.Fatal(err)