build(electron): Bump Electron to v2

[yangchoo]

This addresses the Harfbuzz version too old (1.4.2) error by bumping the underlying electron dependency to the next major version, v2.

Fixed the underyling calls to setZoomLevelLimits with setVisualZoomLevelLimits.

See https://www.electronjs.org/docs/breaking-changes#webcontents

[yangchoo]

Hi there, figured I'll push this PR out since I've gotten it to work on my system with this patch.

I've ran the tests locally, and it seems to be working fine.

[yangchoo]

fwiw, Github actions do not work for forked repos (see https://github.community/t/github-workflow-not-running-from-pull-request-from-forked-repository/16379/47)

I'm happy to help contribute to shift the testing platform to another open-source vendor such as Travis where this functionality exists.

Otherwise, if I could be added to some developer group for pushing to this repo, that'll work as well.

[ghost]

Hello @yangchoo , thank you for making this PR! I will go over it within the week.

[sjaenick]

To build, I had to extend package.json, adding "rwlock": "^5.0.0".