Cross-platform npm scrips using cross-env

[DvdGiessen]

Builds and tests complete flawlessly on Window now (tested on Windows 10).

[Yuyz0112]

Thanks a lot! But the rrweb-snapshot also has the same problem and I would like to:

1. update rrweb-snapshot to use cross-env
2. release a new version of rrweb-snapshot
3. update rrweb-snapshot in rrweb and use cross-env in rrweb too

So we will only have one commit about this in the rrweb repo, would mind me update rrweb-snapshot later today or you also like to contribute this to rrweb-snapshot?

[Yuyz0112]

@DvdGiessen The PR in rrweb-snapshot have been merged, and you can run npm update rrweb-snapshot to update a new version in this PR when you are free.

[TimoStaudinger]

Gave it a try with the changes on my Windows machine, and it looks like it's working perfectly now! 👍

[DvdGiessen]

Rebased on latest master, included new rrweb-snapshot version and re-ran tests successfully on Windows.

[Yuyz0112]

Thanks!