Update Electron version to resolve Snky vulnerabilities.

[scottdonaldau]

These issues do not affect the QRL Wallet repo, however we should update regardless.

Issues identified as vulnerabilities below, with justification as to why we are not vulnerable.

https://snyk.io/vuln/npm:electron:20180307 / https://snyk.io/vuln/npm:electron:20180123

• We do not register an application handle.
• We have not published Windows Electron clients.

https://snyk.io/vuln/npm:electron:20180323

• We have not published Electron clients.

https://snyk.io/vuln/npm:shelljs:20140723

• shelljs is only used in the packaging process as the nodejs scripts run system commands on the build server.
• We have not published Electron clients.

Other low severity items skipped from this issue though will be addressed.

[scottdonaldau]

Two vulnerabilities patched in #180

Future PR will ignore https://snyk.io/vuln/npm:shelljs:20140723 from Snky reports as this component is only executed in CircleCI / Teamcity environments to build Electron Clients.

[scottdonaldau]

Resolved in 69aaf4062d9fabaf4577a32baa228c6ed5a0badc, 3233249b3c107a60a1359c1e4dfef8fdac45fa9f and 1e81a4e3c769ac0c2bf5f6a1513c716617c83ea8