tox: set a max version for black temporarily

Set a temporary maximum version for black as the newest release(es)
are finding problems with code that has not been recently changed.

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

tox.ini

@@ -50,7 +50,7 @@ allowlist_externals =
 [testenv:formatting]
 deps =
     flake8
-    black>=21.8b0
+    black>=21.8b0, <23.11
 commands =
     flake8 sambacc tests
     black --check -v .