Bump progress tracker

Honestly mostly cause we have progress on simplified_commitment in Core, but also our punishment transaction generation stuff is really coming along nicely.

Author: TheBlueMatt

README.md

@@ -5,7 +5,7 @@ Rust-Lightning, not Rusty's Lightning!
 
 Documentation can be found at [docs.rs](https://docs.rs/lightning/)
 
-Currently somewhere near 20% towards usable, published to see if there is any
+Currently somewhere near 40% towards usable, published to see if there is any
 real interest from folks in using a lightning rust library.
 
 The goal is to provide a full-featured but also incredibly flexible lightning