Fix Typo (#472)

Author: fabdelgado

README.md

@@ -5,7 +5,7 @@ Need help? Have questions or suggestions? Join the [![Gitter](https://badges.git
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 # NimBLE-Arduino
-A fork of the NimBLE stack refactored for compilation in the Ardruino IDE.
+A fork of the NimBLE stack refactored for compilation in the Arduino IDE.
 
 **As of release 1.4.0 Nordic Semiconductor nRF51 and nRF52 series devices are now supported**