feat: add link to Google Colab setup guide in README

Author: joshitha1808

README.md

@@ -49,6 +49,7 @@ To get setup for development, see [this video if you prefer VS Code](https://you
 For detailed setup instructions, see:
 - [Linux setup guide](LINUX_SETUP.md)
 - [macOS setup guide](MACOS_SETUP.md)
+- [Google Colab setup guide](docs/source/colab_tpu_runtime.rst)
 Detailed instructions can be found in the [Contributors guide](https://github.com/malariagen/malariagen-data-python/blob/master/CONTRIBUTING.md).
 
 ## AI use policy and guidelines