Dependency: Update to Electron 6

[dehmer]

If there are no serious drawbacks we should update to Electron 6 to keep up to date.

[dehmer]

Inconsistent and (now) invalid usage of ctor/ctor functions in TACGRP prevent upgrading electron/node.js.

[dehmer]

One more reason to upgrade:
https://electronjs.org/blog/electron-7-0#end-of-support-for-4xy

[dehmer]

Although Electron 7.0.1 was just released, we stick to 6.1.2 for now.

[dehmer]

macOS build 6.1.2 crashed with

Exception Type:        EXC_BREAKPOINT (SIGTRAP)
Exception Codes:       0x0000000000000002, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Trace/BPT trap: 5
Termination Reason:    Namespace SIGNAL, Code 0x5
Terminating Process:   exc handler [3879]

see also: electron/electron#19626

[dehmer]

Upgrading electron-builder should fix this problem: nklayman/vue-cli-plugin-electron-builder#390

[dehmer]

Updating electron-builder to 22.1.0 resolves the crashing issue.
macOS build is good for Mojave and Catalina.

[dehmer]

Sadly, electron-builder update breaks Windows builds under macOS Mojave.
But since wine (32 bit) will not be supported for Catalina, we have to build under Windows anyways. Which, by the way, still works with version builder 22.1.0.

Reference: electron-userland/electron-builder#4336