R1:ea337abafb67

Minor tidying of `lipsum generate` workflow

Summary: Just modernizing this a bit.

Test Plan: Ran `./bin/lipsum generate`.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11907