Fixed typo in README.md (openhab#2584)

Signed-off-by: Hilbrand Bouwkamp <hilbrand@h72.nl> (github: Hilbrand)

Author: Hilbrand

README.md

@@ -1,6 +1,6 @@
 ## openHAB 2 Add-ons
 
-This repository contains add-ons that are implemenented using the new [Eclipse SmartHome APIs](https://www.eclipse.org/smarthome/documentation/development/bindings/how-to.html) of openHAB 2.
+This repository contains add-ons that are implemented using the new [Eclipse SmartHome APIs](https://www.eclipse.org/smarthome/documentation/development/bindings/how-to.html) of openHAB 2.
 
 Note that all information about openHAB itself, the IDE setup and the contribution processes can be found in the [openhab-distro](https://github.com/openhab/openhab-distro) project, so please go there for any further details!