Replace deprecated canvas-prebuilt by canvas

[matthieu-foucault]

Fixes #94
I also added the cross-env dev dependency, allowing to run build scripts on windows

[codecov]

Codecov Report

Merging #96 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #96   +/-   ##
=======================================
  Coverage   95.67%   95.67%           
=======================================
  Files          11       11           
  Lines         231      231           
=======================================
  Hits          221      221           
  Misses         10       10

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[michalochman]

Hey @matthieu-foucault, that's not what I wanted to do at all and now I can't revert it. Would you please do it again, but this time also remove canvas-prebuilt from package.json? I have pushed master instead of updated branch to your PR.

Here's the lost commit:
https://github.com/matthieu-foucault/react-pixi-fiber/compare/db0374f48c06136a5045616c0e4267a3d36b5651..0856c28f75ed2e6a5ff4af288e774a11488142c7

[michalochman]

@matthieu-foucault nevermind, I found the commit in my refs with you as the author #97