Add some badges to the README

README.md

@@ -1,10 +1,14 @@
 # bb8
 
+[![Documentation](https://docs.rs/bb8/badge.svg)](https://docs.rs/bb8/)
+[![Crates.io](https://img.shields.io/crates/v/bb8.svg)](https://crates.io/crates/bb8)
+[![Build status](https://github.com/djc/bb8/workflows/CI/badge.svg)](https://github.com/djc/bb8/actions?query=workflow%3ACI)
+[![codecov](https://codecov.io/gh/djc/bb8/branch/main/graph/badge.svg)](https://codecov.io/gh/djc/bb8)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE-MIT)
+
 A full-featured connection pool, designed for asynchronous connections (using
 tokio). Originally based on [r2d2](https://github.com/sfackler/r2d2).
 
-[Documentation](https://docs.rs/bb8)
-
 Opening a new database connection every time one is needed is both inefficient
 and can lead to resource exhaustion under high traffic conditions. A connection
 pool maintains a set of open connections to a database, handing them out for