Email notification hook for dir-auth repository is broken

I think since last week or so my pushes to the dir-auth repository do not create emails to the dir-auth mailing list anymore. Here is the output from today's push

remote: via /srv/git.torproject.org/git-helpers/post-receive-diff
remote: == 00-sync-to-mirror == 
remote: == commit-mail == 
remote: /srv/git.torproject.org/git-helpers/post-receive.d/commit-mail: line 34: formail: command not found
remote: == github-push == 
remote: == gitlab-push == 
remote: == irc-message == 
remote: == per-repo-hook ==