Remove pmm-sumo as Approver (open-telemetry#12493)

* Remove pmm-sumo as Approver

Dear community, due to a transition into another role at a different organisation I am no longer able to allocate time to be an approver of the collector-contrib

Thank you all, it was a great pleasure to work with you and also a great opportunity to learn

* Remove pmm-sumo from auto-assign

.github/auto_assign.yml

@@ -16,7 +16,6 @@ assigneeGroups:
     - djaglowski
     - dmitryax
     - mx-psi
-    - pmm-sumo
     - TylerHelmuth
     # Maintainers
     - bogdandrutu

README.md

@@ -86,9 +86,11 @@ Approvers ([@open-telemetry/collector-contrib-approvers](https://github.com/orgs
 
 - [Anthony Mirabella](https://github.com/Aneurysm9), AWS
 - [David Ashpole](https://github.com/dashpole), Google
-- [Przemek Maciolek](https://github.com/pmm-sumo), Sumo Logic
 - [Tyler Helmuth](https://github.com/TylerHelmuth), New Relic
 
+Emeritus Approvers:
+- [Przemek Maciolek](https://github.com/pmm-sumo)
+
 Maintainers ([@open-telemetry/collector-contrib-maintainer](https://github.com/orgs/open-telemetry/teams/collector-contrib-maintainer)):
 
 - [Alex Boten](https://github.com/codeboten), Lightstep