update tests to skip on CRAN

[erika-tyagi]

Adds testthat::skip_on_cran() in response to the following email from CRAN:

It seems we need to remind you of the CRAN policy:

'Packages which use Internet resources should fail gracefully with an informative message if the resource is not available or has changed (and not give a check warning nor error).'

This needs correction whether or not the resource recovers.

And the following guidance from rOpenSci (here):

Your tests should ideally run without needing an actual internet connection nor the API being up. Your tests that do need to interact with the API should be skipped on CRAN. testthat::skip_on_cran() will ensure that.

Bumps up the version number and rebuilds the package for CRAN resubmission accordingly. Also adds additional test environments.