update MSRV

Author: andrewgazelka

README.md

@@ -8,7 +8,7 @@ This project is developed and maintained by the [HAL team][team].
 
 ## Minimum Supported Rust Version (MSRV)
 
-This crate is guaranteed to compile on stable Rust 1.35 and up. It *might*
+This crate is guaranteed to compile on stable Rust 1.36 and up. It *might*
 compile with older versions but that may change in any new patch release.
 
 ## License