Fix grammar in docstring

CveXplore/main.py

@@ -94,7 +94,7 @@ def __init__(self, **kwargs):
  Args:
  kwargs['datasource_type']: Which datasource to query.
  kwargs['datasource_connection_details']: Provide the connection details needed to establish a connection \
- to the datasource. The connection details should be in line with the datasource it's documentation.
+ to the datasource. The connection details should be in line with the datasource's documentation.
 
  """
  self.__version = VERSION