Add an input for configuring correlator.

[BlakeDickie]

Adds an optional input for manually configuring the correlator string on submissions. If left empty, the existing default generation will run.

[BlakeDickie]

In testing this action, I've found that if we change the inputs that impact the correlator generation (i.e. gradle-build-configuration), then the dependency versions reported by the previous correlator will continue to be included in the dependency graph in GitHub (possibly causing security alerts on old version). They do eventually seems to disappear when a new submission is done after a few days, but for our use, we'd prefer to use a hard coded correlator so we're able to tweak the gradle-build-configuration or job names without worrying about getting duplicate generations, that can cause confusion.

[mikepenz]

Thank you very much for your contribution.