Force the nextrun calculation to use UTC to be consistent with the DB

[discoinfiltrator]

Solves for: humanmade/Cavalcade#74

[discoinfiltrator]

The phpcs violations are not from the file that I modified.

[mackensen]

This fix resolved the DST scheduling issue in our environment.

[discoinfiltrator]

@rmccue can this be looked at so people aren't scrambling when this comes up again in the fall?

[discoinfiltrator]

@rmccue @kadamwhite @missjwo what are the next steps to getting this merged? The DST switchover will be happening soon and it would be amazing to prevent this pretty brutal bug from happening to people.

[roborourke]

I think the code here is good. We haven't run into this issue due to setting our server time to UTC but obviously that's not always something that everyone can or should change.

I need to create a tag of the current version first, then we can merge this in and test it out without potentially affecting production instances.

[discoinfiltrator]

I also 100% agree that the DB, OS, PHP, etc should be using UTC - but sometimes you inherit large systems that are working with their current setup and it'd be tough to change 🙃. Thanks!