v2.2.0-prerelease6

Commits

• 0be200c: set up-to-date header false when not up to date (Felix Haller) #36,#35
• 738bca3: parametrize batch sizes (Felix Haller) #36,#35
• 0a00ba1: use weak etags so gzip is possible (Felix Haller) #36,#35
• 99e9bf3: stop revoked cert sequence from incrementing on every upsert (Felix Haller) #36