fix cannot send multipart to aws due to min size (#319)

lib/record/s3-multipart-upload-stream.js

@@ -16,7 +16,7 @@ class S3MultipartUploadStream extends Writable {
     this.partNumber = 1;
     this.multipartETags = [];
     this.buffer = Buffer.alloc(0);
-    this.minPartSize = 2 * 1024 * 1024; // 5 MB
+    this.minPartSize = 5 * 1024 * 1024; // 5 MB
     this.s3 = new S3Client(opts.bucketCredential);
     this.metadata = opts.metadata;
   }