fix: make package namespace compliant

Author: mima0815

src/fds/__init__.py

@@ -8,3 +8,11 @@
     ConfigurationError,
     JWSSigningError,
 )
+
+import logging
+from logging import NullHandler
+
+# Set default logging handler to avoid "No handler found" warnings.
+# See: https://docs.python.org/3/howto/logging.html#library-config
+logging.getLogger(__name__).addHandler(NullHandler())
+del NullHandler