add Martin's presentation

Author: mnot

Diff for: ietf93/agenda.md

@@ -49,7 +49,7 @@ Discuss the [issues list](https://github.com/httpwg/http-extensions/issues?q=is%
 Discuss possible future work items, including:
 
  * [SEARCH Method](https://tools.ietf.org/html/draft-snell-search-method) - [Presentation](https://httpwg.github.io/wg-materials/ietf93/ietf-93-httpbis-search.pdf) by Julian Reschke
- * New content-codings - Martin Thomson
+ * New content-codings - [Presentation](https://docs.google.com/presentation/d/1rncpm-SRSzVv86lHQipGHi0TXwjoDycXkLGhkwUwB4c/edit#slide=id.p) by Martin Thomson
  * Remaining items on the [watchlist](https://github.com/httpwg/wiki/wiki/WatchList)