v0.7.8

What's Changed

• janitor: replace sets instead of just adding by @aparcar in #357
• misc: service example for multiple workers by @aparcar in #367
• Drop extra_packages stats and use colon in Reds keys by @aparcar in #366
• build: automatically remove unused ImageBuilders by @aparcar in #368

Full Changelog: v0.7.7...v0.7.8