Is it possible to specify docker images for macos executors? I have this matrix in GH Actions that I'd like to port to Circle:
os: ["ubuntu-18.04", "macOS-latest"]
lein-version: ["2.8.1", "2.9.4"]
java-version: ["8", "11", "16"]
not sure if one is supposed to use macos: and docker: at the same time