Update docs/release-notes/v0.28.0.md

Co-authored-by: Aaron Crawfis <[email protected]>
Signed-off-by: Lakshmi Javadekar <[email protected]>

docs/release-notes/v0.28.0.md

@@ -10,7 +10,22 @@ If you're new to Radius, check out our website, [radapp.io](https://radapp.io),
 
 ## Highlights
 
-<!-- TALK TO THE PM TEAM ABOUT WHAT HIGHLIGHTS TO ADD HERE -->
+### New dev container for contributing to the rad CLI
+
+Our new dev container makes it super easy to get up and running with a local dev container or GitHub Codespace in seconds. It's preloaded with everything you need to begin developing the rad CLI and other Radius services. Try it out for free [here](https://github.com/codespaces/new?hide_repo_select=true&ref=main&repo=340522752&skip_quickstart=true&machine=basicLinux32gb&devcontainer_path=.devcontainer%2Fcontributor%2Fdevcontainer.json&geo=UsWest).
+
+[![Open in GitHub Codespaces](https://github.com/codespaces/badge.svg)](https://github.com/codespaces/new?hide_repo_select=true&ref=main&repo=340522752&skip_quickstart=true&machine=basicLinux32gb&devcontainer_path=.devcontainer%2Fcontributor%2Fdevcontainer.json&geo=UsWest)
+
+Thanks to Radius community member @lechnerc77 for the contribution!
+
+### Run Radius behind a custom firewall
+
+Radius installations now support custom certificates to allow Radius to operate behind corporate/custom firewall solutions for enterprise installations. Visit the [Kubernetes installation docs](https://docs.radapp.io/guides/operations/kubernetes/install/#use-your-own-root-certificate-authority-certificate) for more information.
+
+### New test experience when contributing to Radius
+
+Contributing to the Radius project and want to know that your code is fully tested? Our new testing experience makes it easy to easily fork, PR, and make your first commit! Radius now leverages GitHub environments and integrated status checks to make sure that community contributions are good to go. All you need to do is submit your PR and our testing infrastructure will take care of the rest.
+
 
 ## Breaking changes