setup CI to verify that fresh installs run

[klaernie]

I'd like to setup some Github Actions CI, that verifies that the codebase works out of the box with a simple config.

• find a suitable iCalendar feed to use for testing
• setup a Github Action that runs a MagicMirror setup
• run that MagicMirror with testing MMM-CalendarExt2 configs
• verify that setup - maybe with Selenium and some screenshots?

[KristjanESPERANTO]

That would be nice. So far I haven't seen anything like that on any other module. Have you?

[klaernie]

Well, the last point is a moonshot, but the first three shouldn't be too hard.

I guess finding a suitable iCal won't be too hard, after all there are tons of public holiday calendars out there.
Running magic mirror in a container is something I already do at home, so that will be fairly easy.

So while I haven't seen this being done, I see all the pieces and that there should be a way to glue it together.