Update README.md

Fix typo in README, closes #1

README.md

@@ -74,10 +74,10 @@ embeddings.search("query to run")
 Alternatively, the model can be loaded with [sentence-transformers](https://www.SBERT.net).
 
 ```python
-from sentence_transformers import SpladeEncoder
+from sentence_transformers import SparseEncoder
 sentences = ["This is an example sentence", "Each sentence is converted"]
 
-model = SpladeEncoder("neuml/pubmedbert-base-splade")
+model = SparseEncoder("neuml/pubmedbert-base-splade")
 embeddings = model.encode(sentences)
 print(embeddings)
 ```