Adding python 3.10 to tox config

Author: mwatts15

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py27,py37,py38,py39,lint
+    py27,py37,py38,py39,py310,lint
 
 [testenv]
 passenv = DB DBURI
@@ -12,7 +12,7 @@ commands =
 deps =
     psycopg2
     mysqlclient
-    py{37,38,39}: mysql-connector
+    py{37,38,39,310}: mysql-connector
 
 [testenv:lint]
 commands = flake8 rdflib_sqlalchemy test
@@ -39,6 +39,7 @@ python =
     3.7: py37, lint
     3.8: py38
     3.9: py39
+    3.10: py310
 
 [flake8]
 max-line-length = 120