Clean up deprecation warnings (#19654)

* Clean up deprecation warnings

Notes:
Changed some strings in tests to raw strings, which will change the literal content of the strings as they are fed into whatever machine handles them.
Test cases for past in the past/past_key_values switch changed/removed due to warning of impending removal

* Add PILImageResampling abstraction for PIL.Image.Resampling

tests/pipelines/test_pipelines_question_answering.py

@@ -93,7 +93,7 @@ class QAPipelineTests(unittest.TestCase, metaclass=PipelineTestCaseMeta):
             question_answerer(question="In what field is HuggingFace working ?", context=None)
 
         outputs = question_answerer(
-            question="Where was HuggingFace founded ?", context="HuggingFace was founded in Paris.", topk=20
+            question="Where was HuggingFace founded ?", context="HuggingFace was founded in Paris.", top_k=20
         )
         self.assertEqual(
             outputs, [{"answer": ANY(str), "start": ANY(int), "end": ANY(int), "score": ANY(float)} for i in range(20)]