test: integrate lua testing into regular pytest run for push notifications

turns out Python has the nice https://pypi.org/project/lupa/
that allows us to quite easily test dovecot LUA parts
without figuring out errors on deploy.

cmdeploy/pyproject.toml

@@ -19,6 +19,7 @@ dependencies = [
   "pytest-xdist", 
   "execnet",
   "imap_tools",
+  "lupa",
   "deltachat-rpc-client",
   "deltachat-rpc-server",
 ]