fix spelling error

Author: glensc

README.md

@@ -12,7 +12,7 @@ U don't like it? [Watch the doggo](https://twitter.com/RespectfulMemes/status/90
 *P.S. You [don't need to know](https://xkcd.com/1050/) all of that by heart to be a programmer.  
 But knowing the stuff will help you become better! :muscle:*
 
-*P.P.S. [Contributions](CONTRIBUTING.md) are welcomed!*
+*P.P.S. [Contributions](CONTRIBUTING.md) are welcome!*
 
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