feat: provide short version (#1206)

Provides a short version output to assist with CLI parsing.
---------

Co-authored-by: Alex Tocar <alex.tocar@ueuie.dev>

cmd/cloudflared/main.go

@@ -134,11 +134,22 @@ To determine if an update happened in a script, check for error code 11.`,
 		{
 			Name: "version",
 			Action: func(c *cli.Context) (err error) {
+				if c.Bool("short") {
+					fmt.Println(strings.Split(c.App.Version, " ")[0])
+					return nil
+				}
 				version(c)
 				return nil
 			},
 			Usage:       versionText,
 			Description: versionText,
+			Flags: []cli.Flag{
+				&cli.BoolFlag{
+					Name:    "short",
+					Aliases: []string{"s"},
+					Usage:   "print just the version number",
+				},
+			},
 		},
 	}
 	cmds = append(cmds, tunnel.Commands()...)