Update README.md

Author: rgiessmann

README.md

@@ -1,7 +1,7 @@
 # Robert's Farm of Ideas: 1
 
 [![DOI](https://zenodo.org/badge/324523777.svg)](https://zenodo.org/badge/latestdoi/324523777)
-[![License: CC BY 4.0](https://img.shields.io/badge/License-CC%20BY%204.0-lightgrey.svg)](https://creativecommons.org/licenses/by/4.0/)
+[![License: CC BY 4.0](https://img.shields.io/badge/License-CC%20BY%204.0-green.svg)](https://creativecommons.org/licenses/by/4.0/)
 
 
 When determining equilibrium constants of multi-substrate / multi-product reactions, the concentrations may affect the uncertainty of the result.