fix deployment

Author: lavalamp

mungegithub/submit-queue/deployment.yaml

@@ -15,7 +15,6 @@ spec:
         - /mungegithub
         - --token-file=/etc/secret-volume/token
         - --pr-mungers=blunderbuss,lgtm-after-commit,cherrypick-auto-approve,label-unapproved-picks,needs-rebase,ok-to-test,rebuild-request,path-label,size,stale-pending-ci,stale-green-ci,block-path,release-note-label,comment-deleter,submit-queue,issue-cacher,flake-manager,old-test-getter
-        - --do-not-merge-milestones=
         - --dry-run=true
         - --weak-stable-jobs=kubernetes-kubemark-500-gce
         - --required-contexts="Jenkins GCE Node e2e"