Add macos-11.x to test matrix when no longer in preview

## Use Case
*Please provide a use case to help us understand your request in context*

Make sure the module works on macos-11.0 when it becomes available.

## Solution
*Please describe your ideal solution*

add macos-11.0 to the list of environments and that should do it.

## Alternatives
*Please describe any alternatives you've considered, even if you've dismissed them*

Test on a macos-11.0 machine but that's only a stopgap measure.