Add a batch_size param to the add_texts API of pinecone wrapper (#1658)

A safe default value of batch_size is required by the pinecone python
client otherwise if the user of add_texts passes too many documents in a
single call, they would get a 400 error from pinecone.

langchain/vectorstores/pinecone.py

@@ -56,6 +56,7 @@ class Pinecone(VectorStore):
         metadatas: Optional[List[dict]] = None,
         ids: Optional[List[str]] = None,
         namespace: Optional[str] = None,
+        batch_size: int = 32,
         **kwargs: Any,
     ) -> List[str]:
         """Run more texts through the embeddings and add to the vectorstore.
@@ -79,7 +80,7 @@ class Pinecone(VectorStore):
             metadata[self._text_key] = text
             docs.append((ids[i], embedding, metadata))
         # upsert to Pinecone
-        self._index.upsert(vectors=docs, namespace=namespace)
+        self._index.upsert(vectors=docs, namespace=namespace, batch_size=batch_size)
         return ids
 
     def similarity_search_with_score(