NOTICE.md: Electron link outdated

[nimo23]

Bug Description:

In https://github.com/eclipse-theia/theia/blob/master/NOTICE.md#electron, the link https://www.electronjs.org/docs/latest/development/upgrading-chromium#verify-ffmpeg-support returns 404 Not Found.

[tsmaeder]

Thanks for reporting. @marcdumais since you last touched this file, do you know if there's some automation going into collecting the notices in this file?

[marcdumais-work]

do you know if there's some automation going into collecting the notices in this file?

Yes, the rest of the file was auto-generated from the Theia project page, but the Electron notice was "hand-written" and provided by the Eclipse Foundation, following an investigation that we helped-with. I believe the referenced page, that no longer exists, contained an easy test - code to load in an Electron app to determine whether the version of libffmpeg bundled with that app contains the allegedly proprietary codecs or not.

I was able to find alternate sources for the page, however the link for the video at the heart of the test is itself no longer resolving. Look near the bottom of the page:
https://raw.githubusercontent.com/electron/electron/4305657858592be2b44c95ae7af53c627dcdc5e7/docs/development/upgrading-chromium.md