Update MAINTAINERS info

Signed-off-by: Daniel Holbach <daniel@weave.works>

Author: Daniel Holbach

MAINTAINERS

@@ -8,6 +8,8 @@ from the main Flux v2 git repository, as listed in
 
     https://github.com/fluxcd/flux2/blob/main/MAINTAINERS
 
-In alphabetical order:
+Retired maintainers:
 
-Sean Eagan, AT&T <sean.eagan@att.com> (github: @seaneagan, slack: seaneagan)
+- Sean Eagan
+
+Thank you for your involvement, and let us not say "farewell" ...