message: move rand to optional dependencies
  closes
diff: @@ -12,14 +12,13 @@ description = "Fast field codecs used by tantivy"
  common = { path = "../common/" }
  tantivy-bitpacker = { path = "../bitpacker/" }
  prettytable-rs = {version="0.8.0", optional= true}
  -#prettytable-rs = {version="0.8.0" }
  -rand = "0.8.3"
  +rand = {version="0.8.3", optional= true}
  [dev-dependencies]
  more-asserts = "0.2.1"
  rand = "0.8.3"
  [features]
  -bin = ["prettytable-rs"]
  +bin = ["prettytable-rs", "rand"]
  default = ["bin"]
  