Exclude tests from wheel

It's generally not desired to install tests together with the module.
This change does just that and keeps everything else unchanged. Tests
are still included in the sdist.

setup.cfg

@@ -36,10 +36,11 @@ install_requires =
     zarr_checksum
 zip_safe = False
 packages = find_namespace:
-include_package_data = True
+include_package_data = False
 
 [options.packages.find]
 include = dandischema*
+exclude = *tests*
 
 [options.extras_require]
 # I bet will come handy