From: Nathan Phillip Brink <ohnobinki@ohnopublishing.net>
Subject: Fix dependency on alembic to allow newer versions which are compatible.

Only 1.7.0 had an issue. See https://gitlab.com/mailman/mailman/-/commit/bca316448c72868b696cfb06fbd4b3ca3a3580ba#note_790399774 .
--- a/setup.py
+++ b/setup.py
@@ -111,7 +111,7 @@
         },
     install_requires = [
         'aiosmtpd>=1.4.1',
-        'alembic>=1.6.2,<1.7',
+        'alembic>=1.6.2,!=1.7.0',
         'atpublic',
         'authheaders>=0.9.2',
         'authres>=1.0.1',