RUST-808 Update bson dependency to 2.0.0-beta

Author: patrickfreed

Cargo.toml

@@ -34,7 +34,7 @@ bson-u2i = ["bson/u2i"]
 async-trait = "0.1.42"
 base64 = "0.13.0"
 bitflags = "1.1.0"
-bson = { git = "https://github.com/mongodb/bson-rust" }
+bson = "2.0.0-beta"
 chrono = "0.4.7"
 derivative = "2.1.1"
 futures-core = "0.3.14"