update crates-io status

Author: yijunyu

README.md

@@ -1,5 +1,7 @@
 # rust-diagnostics
 
+[![](https://img.shields.io/crates/v/z3.svg)](https://crates.io/crates/rust-diagnostics)
+
 This is a utility to insert diagnostics of code fragments as comments in Rust
 code and checks how a warning/error in the diagnostics has been fixed in git
 commit history.