Desktop: Desktop App issues certificate errors since v3.7.1

[jasonblais]

I confirm (by marking "x" in the [ ] below: [x]):

• [X] This is not a troubleshooting question. Troubleshooting questions go here: http://www.mattermost.org/troubleshoot/.
• [X] This doesn't reproduce on web browsers (such as in Chrome). If it does, issue reports go to the Mattermost Server repository.
• [X] I have read contributing guidelines.

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Summary
Desktop App issues certificate errors since v3.7.1

Steps to reproduce

There are no clear reproduction steps, but at least three separate users have reported certificate errors since v3.7.1:

https://pre-release.mattermost.com/core/pl/4jmwur5fr3no9j1nhg6ntgyfzr
https://pre-release.mattermost.com/core/pl/fyfek1upt7g83jxbh4hfwimf9y
https://pre-release.mattermost.com/private-core/pl/1tcwauk7ibdr9rf1gcz6pf8tur

[jasonblais]

@yuya-oc I know you're already looking into this, but created a ticket for us to track.

@amyblais Added a priority 1 label since it affects the "Trusted" principle.

[yuya-oc]

Probably related: https://github.com/electron/electron/issues/11997 And it might be fixed at Electron 1.8.3.

As an ad-hoc workaround, we might be able to ignore the error by using setVertificateVerifyProc().

[jasonblais]

@amyblais Can you help ask Lindy to download a test build from https://github.com/mattermost/desktop/pull/741 which upgrades Electron to 1.8.4.

If it resolves it for her, then at least we'll know it's related.

[amyblais]

@jasonblais, @yuya-oc FYI, Lindy reported that she hasn't seen the issues anymore with the test build from https://github.com/mattermost/desktop/pull/741.

[jasonblais]

Great! That means it should already be fixed for 4.1.0.

@amyblais Can you also help Lindy to download the test artifact here, which should fix it for 4.0.1: https://github.com/mattermost/desktop/pull/743

[amyblais]

Lindy tested with #743 and saw no issues.
Linda also reported that she has seen no issues with the test build from #741 on Mac.

[jasonblais]

Perfect. @yuya-oc We can merge #743 and the changelog PR once you've reviewed (#744).

We can then close https://github.com/mattermost/desktop/issues/742 and cut 4.0.1-final.