Add stryker integration test

[sgohlke]

We only use unit tests at the moment to check that "shouldIgnore" behaves as we expect it. This does not run Stryker so we cannot be sure that our provided Ignorer actually works with Stryker. We should think of a way to test this.

Ideas:

• Create exampe code and test and run them with VitestRunner like they did in https://github.com/stryker-mutator/stryker-js/blob/master/packages/vitest-runner/test/integration/vitest-test-runner.it.spec.ts
• If possible run Stryker from test code and check results.
• Create example project, reference stryker-log-ignorer from build folder and run stryker for this project and ensure pipeline is green.

Ideas and feedback are welcome.