User agent (#101)

* added sdk version to headers

* Update client.py

* Update _version.py

* format code

* format

* google format

* parse __init__.py for version

* Updated changelog

authored-by: Matt Sokoloff <msokoloff@labelbox.com>

Author: msokoloff1

CHANGELOG.md

@@ -6,6 +6,10 @@
 * Comparing a Labelbox object (e.g. Project) to None doesn't raise an exception
 * Adding `order_by` to `Project.labels` doesn't raise an exception
 
+## Version 2.4.10 (2021-01-05)
+### Added 
+* SDK version added to request headers
+
 ## Version 2.4.9 (2020-11-09)
 ### Fix
 * 2.4.8 was broken for > Python 3.6