Add tox comment

Author: tammy-baylis-swi

tox.ini

@@ -263,6 +263,7 @@ envlist =
     ; below mean these dependencies are being used:
     ; 0: sqlalchemy>=1.1,<1.2
     ; 1: sqlalchemy~=1.4 aiosqlite
+    ; 2: sqlalchemy~=2.0.0
     py3{8,9,10,11,12}-test-instrumentation-sqlalchemy-{1,2}
     pypy3-test-instrumentation-sqlalchemy-{0,1,2}
     lint-instrumentation-sqlalchemy