Added note for bLIP 10 fields removed by #510

Author: ericpp

value/blip-0010.md

@@ -166,6 +166,12 @@ Other optional fields:
 
 <br>
 
+The following fields have been **removed** from the spec and should no longer be used (see [#510](https://github.com/Podcastindex-org/podcast-namespace/pull/510)):
+
+* `pubkey`, `seconds_back`, `sender_key`, `sig_fields`, `value_msat`
+
+<br>
+
 ## Reference Implementations
 
 *