Update this for future pypixelbuf 2.0.0

[tannewt]

It updates the PixelBuf API to match late changes in CircuitPython. adafruit/Adafruit_CircuitPython_Pypixelbuf@1.0.3...master

@dunkmann00 We'll need this before we can release pypixelbuf. Ideally the new versions of both would be released in the same bundle.

[ladyada]

@caternuson wanna take a stab at it?

[tannewt]

Fixed by #15 Thanks @dunkmann00!