Privacy Update and a bugfix

Fix 

First up we fixed an issue where Slack posts would fail if the public holiday country had multiple public holidays on the same day. 

Improvement 

Second up, big privacy improvement to Timetastic: Following our removal of email trackers a while ago, we've removed Google Analytics from the website, app, blog, help centre and this changelog.

We've moved to a privacy focused analytics app called Plausible.

You can read more about Plausible here: https://plausible.io/