message: downgrade serde_json to match rustc workspace
diff: @@ -33,7 +33,7 @@ required-features = ["rustc_tests"]
  cargo_metadata = { version = "0.9.0", optional = true }
  directories = { version = "2.0", optional = true }
  rustc_version = { version = "0.2.3", optional = true }
  -serde_json = { version = "1.0.44", optional = true }
  +serde_json = { version = "1.0.40", optional = true }
  getrandom = { version = "0.1.8", features = ["std"] }
  byteorder = "1.3"
  