README: typo fix

README.md

@@ -134,7 +134,7 @@ In both cases you will end up with a very basic webserver running locally on por
 Tests are written in [Jest](https://jestjs.io/). You can run them using this command in the project directory:
 
 ```bash
-npx jest ./__tests__/'
+npx jest ./__tests__/
 ```
 
 If you don't have NodeJS on your machine, you can run them by using Docker (also in the project directory):