Retire rmfitzpatrick (#734)

👋 I've been absent from this project and my role at Splunk is pretty
much exclusively related to collector items for the foreseeable future.
I do intend to help with the metric gatherer and its improvement as I
can, but have obviously not been contributing as a maintainer for some
time.

Thanks to @trask, @mateuszrzeszutek, and all the other members for
greatly improving this project and keeping it cruising.

---------

Co-authored-by: Trask Stalnaker <trask.stalnaker@gmail.com>

README.md

@@ -58,9 +58,12 @@ Maintainers ([@open-telemetry/java-contrib-maintainers](https://github.com/orgs/
 - [Jack Berg](https://github.com/jack-berg), New Relic
 - [Mateusz Rzeszutek](https://github.com/mateuszrzeszutek), Splunk
 - [Nikita Salnikov-Tarnovski](https://github.com/iNikem), Splunk
-- [Ryan Fitzpatrick](https://github.com/rmfitzpatrick), Splunk
 - [Trask Stalnaker](https://github.com/trask), Microsoft
 
+Emeritus maintainers:
+
+- [Ryan Fitzpatrick](https://github.com/rmfitzpatrick), Splunk
+
 Learn more about roles in the [community repository](https://github.com/open-telemetry/community/blob/master/community-membership.md).
 
 Thanks to all the people who already contributed!