feat: disable macOS cli tests (#857)

Author: Rebecca Graber

.github/workflows/cli-tests.yml

@@ -24,8 +24,11 @@ jobs:
         os:
           - name: linux
             image: ubuntu-20.04 # Focal Fossa
-          - name: mac
-            image: macos-10.15 # Catalina
+          # The virtual environment for mac10.15 is currently using a version of VirtualBox
+          # that is incompatible. Commenting out the mac tests until this is addressed.
+          # See https://github.com/actions/virtual-environments/issues/4466 for details
+          # - name: mac
+            # image: macos-10.15 # Catalina
         python-version:
           - '3.8'
       fail-fast: false
@@ -58,9 +61,8 @@ jobs:
           path: ~/.docker/machine/cache
           key: ${{ runner.os }}-docker-machine
 
-      # TODO: Stop using boot2docker, which is contradindicated in the
-      # README. (Not sure how to install Docker for Desktop here,
-      # though.)
+      # Note: we have to use boot2docker because Docker Desktop has not been licensed
+      # for use in GithubActions
       #
       # This also only seems to work for the CLI tests, not the
       # provisioning tests, even with apparently identical scripts.