1.2.0

What's Changed

• html improvements by @Iain-S in #17
• Readthedocs by @Iain-S in #19
• Docs installation by @Iain-S in #23
• Give short intro by @Iain-S in #24
• Don't rely on UUID(int=0) subscription existing in db by @Iain-S in #28
• Update integrity checks and schema name by @Iain-S in #26
• Use celery to schedule periodic tasks by @Iain-S in #27
• Update fastapimsal library by @Iain-S in #29

Full Changelog: 1.1.2...1.2.0