mod(cli): remove version command and replace with flag instead

cmd/root.go

@@ -8,7 +8,10 @@ import (
 	"github.com/spf13/viper"
 )
 
+const VERSION string = "0.1"
+
 var (
+	version bool
 	dry_run bool
 	rootCmd = &cobra.Command{
 		Use:   "gitw",
@@ -24,6 +27,9 @@ func Execute() error {
 
 func init() {
 	cobra.OnInitialize(initConfig)
+	// version flag
+	rootCmd.Flags().BoolVarP(&version, "version", "v", false, "Print version of gitwarrior")
+	rootCmd.Version = VERSION
 }
 
 func initConfig() {