Remove Contributor License Agreement (CLA) in favor of certification in contributing.md (#267)

Signed-off-by: Will Engler <[email protected]>

Author: WillEngler

.github/PULL_REQUEST_TEMPLATE.md

@@ -10,5 +10,6 @@ Before a pull request can be merged, the following items must be checked:
 * [ ] Doc strings have been added in the [Google docstring format](https://sphinxcontrib-napoleon.readthedocs.io/en/latest/example_google.html#example-google).
 * [ ] Run [ruff](https://beta.ruff.rs/docs/rules/#pydocstyle-d) on your code.
 * [ ] Tests have been added for any new functionality or bug fixes.
+* [ ] I have read and agree to the Contributor's Certification in [CONTRIBUTING.md](CONTRIBUTING.md).
 
 We highly recommended installing the pre-commit hooks running in CI locally to speedup the development process. Simply run `pip install pre-commit && pre-commit install` to install the hooks which will check your code before each commit.

CONTRIBUTING.md

@@ -1,14 +1,18 @@
 # Contributing to TorchSim
 
-TorchSim is an experimental library and we would appreciate any feedback from the community.
+TorchSim welcomes contributions and feedback from the community.
 
-## Contributor License Agreement (CLA)
+## Contributor's Certification
 
-Before contributing, you'll need to sign our Contributor License Agreement (CLA). This is a one-time requirement that covers all Radical AI open source projects. The CLA allows you to maintain ownership of your contributions while granting Radical AI the necessary rights to use them.
+By making a contribution to this project, you certify that you agree to the following:
 
-[Radical AI CLA](https://www.radical-ai.com/oss)
+(a) The contribution was created in whole or in part by me and I have the right to submit it under the open source license indicated in the file; or
 
-Our CLA-bot will automatically verify your signature on pull requests. For questions about the CLA, contact [email protected].
+(b) The contribution is based upon previous work that, to the best of my knowledge, is covered under an appropriate open source license and I have the right under that license to submit that work with modifications, whether created in whole or in part by me, under the same open source license (unless I am permitted to submit under a different license), as indicated in the file; or
+
+(c) The contribution was provided directly to me by some other person who certified (a), (b) or (c) and I have not modified it.
+
+(d) I understand and agree that this project and the contribution are public and that a record of the contribution (including all personal information I submit with it) is maintained indefinitely and may be redistributed consistent with this project or the open source license(s) involved.
 
 ## Code Reviews