message: log: Add `std` feature.
  ## Motivation
  Fixes
  ## Solution
  Adds the `log/std` feature.
  Side note: how did the CI pass previously? This doesn't even compile on my machine?
diff: @@ -7,7 +7,7 @@ edition = "2018"
  [dependencies]
  tracing-core = "0.1.2"
  tracing-subscriber = { path = "../tracing-subscriber" }
  -log = "0.4"
  +log = { version = "0.4", features = ["std"] }
  lazy_static = "1.3.0"
  [badges]
  