Set isFractionalZoomEnabled to true

[RobertVogt]

Issue description
Google zoom does not match OpenLayers zoom

Steps to reproduce and a minimal demo of the problem
Overlay OpenLayers vector map on AGM map zoom in and you'll see the zoom does not match.
_Use stackblitz.com or similar -- try this template as a starting point: https://stackblitz.com/edit/angular-google-maps-demo

What steps should we try in your demo to see the problem?

Current behavior
Zooming with AGM providing imagery to a OpenLayers map does not zoom frectional even though google provides this an an option.

Expected/desired behavior
I should be able to set value isFractionalZoomEnabled to true to allow GM to have an infinite amount of zoom levels.

angular-google-maps, Angular, & any other relevant dependency versions
OpenLayers version 6.6.0

Other information
NA

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.