Adding a DependencyCheck runner.

[Torxed]

trafficstars

Mainly for future prep, when we start using external dependencies. This should at least give us a basic safety check against some known issues.

I might have misunderstood DependencyCheck support for Python?: https://github.com/jeremylong/DependencyCheck/pull/5025

[svartkanin]

@Torxed is this something we need?

[Torxed]

It's meant to alert us if we need to urgently bump a version. But if we use renovate to always stay up to date - that could work too as there's nothing more we can do besides upgrading.