Update links to the last version (sfackler#248)

* Update docs.rs to links to the last version

* Update the version displayed in the README

Author: Kerollmops

README.md

@@ -1,14 +1,14 @@
 # Rust-Postgres
 A native PostgreSQL driver for Rust.
 
-[Documentation](https://docs.rs/postgres/0.13.4/postgres)
+[Documentation](https://docs.rs/postgres)
 
 [![Build Status](https://travis-ci.org/sfackler/rust-postgres.svg?branch=master)](https://travis-ci.org/sfackler/rust-postgres) [![Latest Version](https://img.shields.io/crates/v/postgres.svg)](https://crates.io/crates/postgres)
 
 You can integrate Rust-Postgres into your project through the [releases on crates.io](https://crates.io/crates/postgres):
 ```toml
 [dependencies]
-postgres = "0.13"
+postgres = "0.14"
 ```
 
 ## Overview