Update maintenance.md

Author: SethTisue

doc/maintenance.md

@@ -40,6 +40,7 @@ Tips for addressing gradually dwindling free space:
       There are different ways to do this; see e.g.
       [this Stack Overflow question](https://stackoverflow.com/questions/13052390/jenkins-remove-old-builds-with-command-line).
       Example command that worked for me: `curl -u SethTisue:myauthkey -X POST 'https://scala-ci.typesafe.com/job/scala-2.11.x-integrate-community-build/[750-900]/doDelete'` where `SethTisue` is my GitHub user name and `myauthkey` is actually a hex thing I generated [on GitHub](https://github.com/settings/tokens).
+     (Jul 30 2020) gah but last time I tried this I hit https://github.com/spinnaker/spinnaker/issues/2067 — not sure what to do 
 
 Tips for addressing a temporary free-space issue on the behemoths: