Update mongodb driver to 2.x (#16)

* Bump mongodb to 2.x
* Add chrono feature flag
* Remove cargo.lock
* Update CHANGELOG.md
* Bump version

Author: Samuel-B-D

.gitignore

@@ -1,2 +1,3 @@
 /target
-.idea
+.idea
+Cargo.lock

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.8.0] 2021-12-09
+
+### Changed
+
+- **BREAKING:** Update `mongodb` to `2.x`
+
 ## [0.7.0] 2021-05-01
 
 ### Changed