Fix with nettle >=4

Index: lib/nettle-hmac.c
--- lib/nettle-hmac.c.orig
+++ lib/nettle-hmac.c
@@ -37,6 +37,6 @@ void hmac_md5_with_nettle(uint8_t *data, size_t  data_
     memset(digest, 0, MD5_DIGEST_SIZE);
     hmac_md5_set_key(&md5, key_len, key);
     hmac_md5_update(&md5, data_len, data);
-    hmac_md5_digest(&md5, MD5_DIGEST_SIZE, digest);
+    hmac_md5_digest(&md5, digest);
 }
 
