Update README.md

[silabs-Prens]

Updating the Silicon Labs repo reference to a more comprehensive and up-to date repository.

BUG=N/A

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[veblush]

Thanks for the PR.

[veblush]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

Would you resolve this CLA issue?

[silabs-Prens]

Hello!
Unfortunately, as I found, we do not have a contribution agreement! Could I maybe open an issue to request some other contributor to merge the changes in the link?