3.22.0

• Mark $convert and $toLong operators as not implemented yet
• Handle negative limit values for cursor
• Add filter kwarg to list_collection_names (#681)
• Align equality and hashable capacity on Pymongo's object
• Really run tests for Python 3.9
• Add typing stubs
• Add the collation property to Cursor
• Add Python 3.9 to the test matrix
• Accept collation kwarg in update_one and update_many
• Performance improvement: create only one instance of _Filterer (#674)
• Implement '$concatArrays' aggregation pipeline operator (#672)