moved the sigmoid_linear_unit.py from maths/ to neural_network/activation_functions

CONTRIBUTING.md

@@ -1,5 +1,18 @@
 # Contributing guidelines
 
+## Contribution Checklist
+
+- [ ] Read the [Code of Conduct](CODE_OF_CONDUCT.md).
+- [ ] Fork the repository.
+- [ ] Clone the repository to your local machine.
+- [ ] Create a new branch for your changes.
+- [ ] Implement your changes and commit them.
+- [ ] Push your changes to your forked repository.
+- [ ] Create a pull request.
+- [ ] Review and address feedback from maintainers.
+- [ ] Yay! Your pull request is merged. 
+
+
 ## Before contributing
 
 Welcome to [TheAlgorithms/Python](https://github.com/TheAlgorithms/Python)! Before sending your pull requests, make sure that you __read the whole guidelines__. If you have any doubt on the contributing guide, please feel free to [state it clearly in an issue](https://github.com/TheAlgorithms/Python/issues/new) or ask the community in [Gitter](https://gitter.im/TheAlgorithms/community).