Update README.md

Author: rudolphpienaar

README.md

@@ -31,7 +31,7 @@
 Please submit pull request, open issues or contact us for any question, feature request, etc.
 
 - <Important Note>
--  Developper preview means that the API might change but you can already build cool apps with AMI.
+-  Developer preview means that the API might change but you can already build cool apps with AMI.
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