update approvers/maintainers list (#614)

Author: alrex

README.md

@@ -79,15 +79,17 @@ Meeting notes are available as a public [Google doc](https://docs.google.com/doc
 Approvers ([@open-telemetry/python-approvers](https://github.com/orgs/open-telemetry/teams/python-approvers)):
 
 - [Aaron Abbott](https://github.com/aabmass), Google
-- [Diego Hurtado](https://github.com/ocelotl), Lightstep
-- [Owais Lone](https://github.com/owais), Splunk
+- [Alex Boten](https://github.com/codeboten), Lightstep
+- [Nathaniel Ruiz Nowell](https://github.com/NathanielRN), AWS
+- [Srikanth Chekuri](https://github.com/lonewolf3739)
 
 *Find more about the approver role in [community repository](https://github.com/open-telemetry/community/blob/main/community-membership.md#approver).*
 
 Maintainers ([@open-telemetry/python-maintainers](https://github.com/orgs/open-telemetry/teams/python-maintainers)):
 
-- [Alex Boten](https://github.com/codeboten), Lightstep
+- [Diego Hurtado](https://github.com/ocelotl), Lightstep
 - [Leighton Chen](https://github.com/lzchen), Microsoft
+- [Owais Lone](https://github.com/owais), Splunk
 
 *Find more about the maintainer role in [community repository](https://github.com/open-telemetry/community/blob/main/community-membership.md#maintainer).*