Adds opt-in multisite support to settings

Bump version

Support for Google Analytics 4

Allow guzzle 7

Add installers

Upgraded tracker code to Universal Analytics (gtag.js) (#100)

Closes #95

Update version to 1.2.4 (#86)

Credit to @gergo85.

Remove @rc constraint form google/apiclient (#75)

Fixes #72. Credit to @acasar