message: Make qrcode dependency optional
diff: @@ -74,7 +74,7 @@ server = ["shadowsocks-service/server"]
  # Enable manager server
  manager = ["shadowsocks-service/manager"]
  # Enable utility
  -utility = []
  +utility = ["qrcode"]
  # Enable service
  service = ["local", "server", "manager"]
  @@ -146,7 +146,7 @@ thiserror = "1.0"
  clap = { version = "3.1", features = ["wrap_help", "suggestions"] }
  cfg-if = "1"
  -qrcode = { version = "0.12", default-features = false }
  +qrcode = { version = "0.12", default-features = false, optional = true }
  exitcode = "1"
  build-time = "0.1"
  directories = "4.0"
  