Use relative release badge in README.

We still are missing a way to compare changes for the most recent release, but at least we're down to one version tag to change.

Author: terrillmoore

README.md

@@ -17,7 +17,7 @@ For general info, we suggest you check the stmm32duino [README.md](https://githu
 
 ## Latest release
 
-[![GitHub release](https://img.shields.io/github/release/mcci-catena/Arduino_Core_STM32.svg)](https://github.com/mcci-catena/Arduino_Core_STM32/releases/latest) [![GitHub commits](https://img.shields.io/github/commits-since/mcci-catena/Arduino_Core_STM32/v1.0.6-mcci.svg)](https://github.com/mcci-catena/Arduino_Core_STM32/compare/v1.0.6-mcci...master)
+[![GitHub release](https://img.shields.io/github/release/mcci-catena/Arduino_Core_STM32.svg)](https://github.com/mcci-catena/Arduino_Core_STM32/releases/latest) [![GitHub commits](https://img.shields.io/github/commits-since/mcci-catena/Arduino_Core_STM32/latest.svg)](https://github.com/mcci-catena/Arduino_Core_STM32/compare/v1.0.6-mcci...master)
 
 ## Getting Started
 
@@ -37,4 +37,4 @@ If you have any issue, you may [file an issue on Github](https://github.com/mcci
 
 ## Support Open-Source Software, Hardware, and Community IoT!
 
-Everyone at MCCI invests time and resources providing this open-source code and open-source hardware. MCCI is also the principal corporate sponsor of [The Things Network New York](https://thethings.nyc) and [Ithaca](https://ttni.tech). Please support our work by purchasing products from MCCI!
+Everyone at MCCI invests time and resources providing this open-source code and open-source hardware. MCCI is also the principal corporate sponsor of [The Things Network New York](https://thethings.nyc) and [Ithaca](https://ttni.tech). Please support our work by purchasing products from MCCI!