Change gem -> project in license

Author: leonid-shevtsov

README.md

@@ -163,7 +163,7 @@ pip install --force-reinstall -v "mailtrap==1.0.1"
 
 ## License
 
-The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
+The project is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
 
 ## Code of Conduct