message: cli: fix structopt syntax
diff: @@ -7,7 +7,7 @@ use structopt::StructOpt;
  #[derive(Debug, StructOpt)]
  pub(crate) struct CliOptions {
  /// Verbosity level (higher is more verbose).
  - #[structopt(short = "v", parse(from_occurrences), raw(global = "true"))]
  + #[structopt(short = "v", parse(from_occurrences), global = true)]
  verbosity: u8,
  /// CLI sub-command.
  