Move existing approvers to maintainers (aws-observability#968)

* Move existing approvers to maintainers

* Order alphabetically

Co-authored-by: Trask Stalnaker <[email protected]>

---------

Co-authored-by: Trask Stalnaker <[email protected]>

Author: arminru

README.md

@@ -106,9 +106,7 @@ Here is a list of community roles with current and previous members:
 
 - Approvers ([@open-telemetry/lambda-extension-approvers](https://github.com/orgs/open-telemetry/teams/lambda-extension-approvers)):
 
-   - [Raphael Philipe Mendes da Silva](https://github.com/rapphil), AWS
    - [Tristan Sloughter](https://github.com/tsloughter), Splunk
-   - [Tyler Benson](https://github.com/tylerbenson), Lightstep
 
 - Emeritus Approvers:
 
@@ -117,6 +115,9 @@ Here is a list of community roles with current and previous members:
 
 - Maintainers ([@open-telemetry/lambda-extension-maintainers](https://github.com/orgs/open-telemetry/teams/lambda-extension-maintainers)):
 
+   - [Raphael Philipe Mendes da Silva](https://github.com/rapphil), AWS
+   - [Tyler Benson](https://github.com/tylerbenson), Lightstep
+
 - Emeritus Maintainers:
 
    - [Alex Boten](https://github.com/codeboten), Lightstep