Drop unused dependencies from collector

Author: Mark-Simulacrum

Cargo.lock

@@ -15,19 +15,14 @@ serde_json = "1"
 tempfile = "3"
 libc = "0.2"
 chrono = "0.4"
-cargo_metadata = "0.9"
 lazy_static = "1"
 semver = "0.9"
 reqwest = { version = "0.10", features = ["json"] }
 xz2 = "0.1.3"
 tar = "0.4"
 crossbeam-channel = "0.4.2"
-bincode = "1"
-snap = "1.0"
-hashbrown = "0.7.0"
 tokio = { version = "0.2", features = ["rt-core"] }
 rustc-artifacts = "0.2"
-parking_lot = "0.10"
 database = { path = "../database" }
 intern = { path = "../intern" }
 futures = "0.3.5"