compatcheck: support macosx

roles/compatcheck/meta/argument_specs.yaml

@@ -22,6 +22,7 @@ argument_specs:
               - ubuntu
               - fedora
               - archlinux
+              - macosx
           version_min:
             description: Earliest supported major version. Allows any version if not specified.
             type: int
@@ -31,7 +32,9 @@ argument_specs:
             type: int
             required: false
           package_managers:
-            description: List of supported package managers. Defaults to apt for debian and ubuntu, dnf for fedora, pacman for archlinux
+            description: >-
+              List of supported package managers. Defaults to apt for debian and ubuntu,
+              dnf for fedora, pacman for archlinux, homebrew for macosx
             type: list
             required: false
             elements: str
@@ -40,3 +43,4 @@ argument_specs:
               - dnf
               - pacman
               - atomic_container
+              - homebrew