Re-enable deprecation checking in CI

Author: abravalheri

tox.ini

@@ -4,8 +4,7 @@ deps =
 	# Ideally all the dependencies should be set as "extras"
 setenv =
 	PYTHONWARNDEFAULTENCODING = 1
-	SETUPTOOLS_ENFORCE_DEPRECATION = {env:SETUPTOOLS_ENFORCE_DEPRECATION:0}
-	# ^-- Temporarily disable enforcement so CI don't fail on due dates
+	SETUPTOOLS_ENFORCE_DEPRECATION = {env:SETUPTOOLS_ENFORCE_DEPRECATION:1}
 commands =
 	pytest {posargs}
 usedevelop = True