fix: add preprocessor_config.json

copied from https://huggingface.co/DunnBC22/wav2vec2-base-Speech_Emotion_Recognition/blob/main/training_args.bin
config for preprocessing

preprocessor_config.json

@@ -0,0 +1,9 @@
+{
+  "do_normalize": true,
+  "feature_extractor_type": "Wav2Vec2FeatureExtractor",
+  "feature_size": 1,
+  "padding_side": "right",
+  "padding_value": 0.0,
+  "return_attention_mask": false,
+  "sampling_rate": 16000
+}