Fix Travis CI badge

Author: laerling

README.md

@@ -1,6 +1,6 @@
 # Rust Ethernet Driver for STM32F* microcontrollers
 
-[![Build Status](https://travis-ci.org/astro/stm32-eth.svg?branch=master)](https://travis-ci.org/astro/stm32-eth)
+[![Build Status](https://travis-ci.org/stm32-rs/stm32-eth.svg?branch=master)](https://travis-ci.org/stm32-rs/stm32-eth)
 
 ## Supported microcontrollers