Worker: make -version CLI option show the 'extended' version

`flamenco-worker -version` now shows the 'extended' version. This is just
the application version when running a release build. Otherwise it will
be like `3.3-alpha0 (v3.2-nn-ghhhhhh)`, where `nn` is the number of commits
since the last-tagged version (`v3.2` in this example), and `ghhhhhh` is
the Git hash. This can optionally be suffixed by `-dirty` if there were
any uncommitted changes when Flamenco was built.

cmd/flamenco-worker/main.go

@@ -52,7 +52,7 @@ var cliArgs struct {
 func main() {
 	parseCliArgs()
 	if cliArgs.version {
-		fmt.Println(appinfo.ApplicationVersion)
+		fmt.Println(appinfo.ExtendedVersion())
 		return
 	}