Release 6.0.0b4, support Python 3

I was considering waiting for a non-beta release; however this adds two
nice benefits:
1. Support for Python 3
2. It should still work against cassandra 3.x clusters. Versus newer
releases likely will require setting the `--cqlversion` flag due to
CASSANDRA-16508.

README.md

@@ -34,9 +34,15 @@ Unfortunately the Cassandra project does not always increment the `cqlsh` versio
 release we need to document not only the `cqlsh` version but also the `cassandra` version in which it
 shipped.
 
+#### 6.0.0b4 (Mar 9, 2022)
+
+This packages `cqlsh` `5.0.1` from [Cassandra 4.0-beta4](https://github.com/apache/cassandra/blob/cassandra-4.0-beta4/bin/cqlsh.py):
+* Now supports Python 3.
+* Although this is pulled from a Cassandra `4.x` release, it should generally work against Cassandra `3.x` clusters without needing to set any flags. Upcoming releases will need to set the `--cqlversion` flag when talking with clusters < `4.0` due to this [commit](https://github.com/apache/cassandra/commit/c9d6c725dd0b4aa5693eb1c6d2221c28e9e99c6e#diff-9e4fe0cfd28004625a8006be8a0bdeab8cbdfb039449fb9501b15e8952577aaaL479). See also [CASSANDRA-16508](https://issues.apache.org/jira/browse/CASSANDRA-16508).
+
 #### 5.0.5 (Mar 9, 2022)
 
-This packages `cqlsh` `5.0.1` from Cassandra version (3.11.10)[https://github.com/apache/cassandra/blob/cassandra-3.11.10/bin/cqlsh.py].
+This packages `cqlsh` `5.0.1` from [Cassandra 3.11.10](https://github.com/apache/cassandra/blob/cassandra-3.11.10/bin/cqlsh.py).
 
 #### 5.0.4 (Mar 29, 2017)
 

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = cqlsh
-version = 5.0.5
+version = 6.0.0b4
 author = Jeff Widman
 author_email = [email protected]
 description = cqlsh is a Python-based command-line client for running CQL commands on a cassandra cluster.
@@ -19,9 +19,16 @@ classifiers =
     Programming Language :: Python
     Programming Language :: Python :: 2
     Programming Language :: Python :: 2.7
+    Programming Language :: Python :: 3
+    Programming Language :: Python :: 3.4
+    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
 
 [options]
 packages = cqlshlib
-python_requires = ~= 2.7
+python_requires = >= 2.7
 # Dependencies are in setup.py for GitHub's dependency graph.
 scripts = cqlsh