Change the release to 3.0.0

In preparation for removing support for the NuoDB Agent, increase the
major version.

Author: madscientist

pynuodb/__init__.py

@@ -1,12 +1,12 @@
-"""Classes containing the exceptions for reporting errors.
+"""An implementation of Python PEP 249 for NuoDB.
 
 (C) Copyright 2013-2023 Dassault Systemes SE.  All Rights Reserved.
 
 This software is licensed under a BSD 3-Clause License.
 See the LICENSE file provided with this software.
 """
 
-__version__ = '2.6.1'
+__version__ = '3.0.0'
 
 from .connection import *
 from .datatype import *