Small typo in readme

Author: patrickfav

README.md

@@ -250,7 +250,7 @@ import static at.favre.lib.bytes.BytesTransformers.*;
 ```java
 Bytes.wrap(array).transform(hmacSha256(macKey32Byte));
 Bytes.wrap(array).transform(hmacSha1(macKey20Byte));
-Bytes.wrap(array).transform(hmac(macKey20Byte,"HmacMd5"));
+Bytes.wrap(array).transform(hmac(macKey16Byte,"HmacMd5"));
 ```
 
 **Checksum** can be calculated or automatically appended: