chore: update to v2.9.0

Author: bathienle

setup.py

@@ -25,7 +25,7 @@
 
 setup(
     name='cytomine-python-client',
-    version='2.8.3',
+    version='2.9.0',
     description='Python client to interact with Cytomine.',
     long_description=long_description,
     long_description_content_type="text/markdown",