setup.cfg: add sambacc.schema to package list

Annoyingly, the tests passed and nothing seemed amiss at first, but
the package was missing from the list.

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

Author: phlogistonjohn

setup.cfg

@@ -13,7 +13,7 @@ url = https://github.com/samba-in-kubernetes/sambacc
 license = GPL3
 
 [options]
-packages = sambacc, sambacc.commands
+packages = sambacc, sambacc.commands, sambacc.schema
 include_package_data = True
 
 [options.entry_points]