libusb on Linux only

Author: tannewt

.github/actions/deps/ports/zephyr-cp/action.yml

@@ -4,6 +4,7 @@ runs:
   using: composite
   steps:
     - name: Get libusb
+      if: runner.os == 'Linux'
       run: |
         sudo apt-get update
         sudo apt-get install -y libusb-1.0-0-dev