Update README.md

Author: cheny0y0

docs/contribute/README.md

@@ -7,5 +7,6 @@
 4. Update your files to [144881-Studios/physics-engine/source-blocks/](https://github.com/144881-Studios/physics-engine/tree/master/source-blocks/) and open a pull request.
 5. Wait for audit.
 6. Well done!
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 [Contribute to us](https://144881-studios.github.io/physics-engine/contribute) [Email to us](mailto:cyy144881@icloud.com?subject=Scratch%203.0%20physics%20engine)