ports/windows: Remove appveyor.yml
ports/windows: Remove appveyor.yml

.. this allows developers who want to work with both micropython and
circuitpython to enable appveyor on their fork, but not get errors
when pushing circuitpython changes.

In the appveyor configuration for your fork, simply enable the
checkbox "Skip branches without appveyor.yml".

adafruit/circuitpython,adafruit/circuitpython,adafruit/micropython,adafruit/micropython,adafruit/circuitpython,adafruit/micropython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/micropython,adafruit/micropython