Update CONTRIBUTING.md to clarify contribution types

CONTRIBUTING.md

@@ -9,6 +9,18 @@ Contributions to this project are [released](https://help.github.com/articles/gi
 
 Please note that this project is released with a [Contributor Code of Conduct](CODE_OF_CONDUCT.md). By participating in this project you agree to abide by its terms.
 
+## What kinds of contributions we're looking for
+
+We'd love your help with:
+
+ * Fixing any bugs in the existing feature set
+ * Making the SDKs more idiomatic and nice to use for each supported language
+ * Improving documentation
+
+If you have ideas for entirely new features, please post an issue or start a discussion. We're very open to new features but need to make sure they align with the direction of the underlying Copilot CLI and can be maintained in sync across all our supported languages.
+
+Currently **we are not looking to add SDKs for other languages**. If you want to create a Copilot SDK for another language, we'd love to hear from you, and we may offer to link to your SDK from our repo. However we do not plan to add further language-specific SDKs to this repo in the short term, since we need to retain our maintenance capacity for moving forwards quickly with the existing language set. So, for any other languages, please consider running your own external project.
+
 ## Prerequisites for running and testing code
 
 This is a multi-language SDK repository. Install the tools for the SDK(s) you plan to work on: