update indices

Author: mnot

ietf122/README.md

@@ -7,4 +7,5 @@
 - [Agenda](agenda.md) 
 - [Ietf HTTPbis 2025-03 Query](ietf-httpbis-2025-03-query.pdf) _pdf_
 - [Ietf HTTPbis 2025-03 Query](ietf-httpbis-2025-03-query.xhtml) _xhtml_
+- [Incremental](incremental.pdf) _pdf_
 - [Resumable Uploads](resumable-uploads.pdf) _pdf_