cohere[minor]: Add cohere rerank

libs/langchain-cohere/src/cohere_rerank.ts

@@ -0,0 +1,12 @@
+import { BaseDocumentCompressor } from "@langchain/core/retrievers/document_compressors/base";
+
+export interface CohereRerankArgs {};
+
+/**
+ * Document compressor that uses `Cohere Rerank API`.
+ */
+export class CohereRerank extends BaseDocumentCompressor {
+  constructor() {
+    super();
+  }
+}