add juliano as a maintainer (#581)

* add juliano as a maintainer

* nit

README.md

@@ -74,19 +74,22 @@ documentation. Our [SIG Calls](CONTRIBUTING.md#join-a-sig-call) are Mondays at
 
 - [Austin Parker](https://github.com/austinlparker), Lightstep
 - [Carter Socha](https://github.com/cartersocha), Lightstep
-- [Morgan McLean](https://github.com/mtwo), Splunk
+- [Juliano Costa](https://github.com/julianocosta89), Dynatrace
 - [Pierre Tessier](https://github.com/puckpuck), Honeycomb
 
 [Approvers](https://github.com/open-telemetry/community/blob/main/community-membership.md#approver)
 ([@open-telemetry/demo-approvers](https://github.com/orgs/open-telemetry/teams/demo-approvers)):
 
-- [Juliano Costa](https://github.com/julianocosta89), Dynatrace
 - [Michael Maxwell](https://github.com/mic-max), Microsoft
 - [Mikko Viitanen](https://github.com/mviitane), Dynatrace
 - [Penghan Wang](https://github.com/wph95), AppDynamics
 - [Reiley Yang](https://github.com/reyang), Microsoft
 - [Ziqi Zhao](https://github.com/fatsheep9146), Alibaba
 
+Emeritus Maintainers
+
+- [Morgan McLean](https://github.com/mtwo), Splunk
+
 ### Thanks to all the people who have contributed
 
 [![contributors](https://contributors-img.web.app/image?repo=open-telemetry/opentelemetry-demo)](https://github.com/open-telemetry/opentelemetry-demo/graphs/contributors)