fix: resolve logger warnings (#1598)

Signed-off-by: Emmanuel Ferdman <emmanuelferdman@gmail.com>

Author: emmanuel-ferdman

sbi/samplers/rejection/rejection.py

@@ -244,7 +244,7 @@ def accept_reject_sample(
         acceptance rates for each observation.
     """
     if kwargs:
-        logging.warn(
+        logging.warning(
             f"You passed arguments to `rejection_sampling_parameters` that "
             f"are unused when you do not specify a `proposal` in the same "
             f"dictionary. The unused arguments are: {kwargs}"