Remove nslaughter as approver (#1668)

Author: nslaughter

README.md

@@ -110,8 +110,6 @@ 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)):
 
-  - [Nathan Slaughter](https://github.com/nslaughter), Lightstep
-
 - Emeritus Approvers:
 
   - [Lei Wang](https://github.com/wangzlei)