replace version command with flag

cmd/cmd_root.go

@@ -104,6 +104,7 @@ var rootCmd = &cobra.Command{
 	Use:   "osem_notify",
 	Short: "Root command displaying help",
 	Long:  "Run healthchecks and send notifications for boxes on opensensemap.org",
+	Version: "1.3.0",
 	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
 		// set up logger
 		log.SetOutput(os.Stdout)

cmd/cmd_version.go

@@ -1,26 +0,0 @@
-package cmd
-
-import (
-	"fmt"
-
-	"github.com/spf13/cobra"
-)
-
-// TODO: insert automatically via build step?
-const (
-	VERSION   = "1.3.0"
-	BUILDDATE = "2019-02-10T16:00:00+00"
-)
-
-func init() {
-	rootCmd.AddCommand(versionCmd)
-}
-
-var versionCmd = &cobra.Command{
-	Use:   "version",
-	Short: "Get build and version information",
-	Long:  "osem_notify version returns its build and version information",
-	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Printf("%s %s", VERSION, BUILDDATE)
-	},
-}