Update README.md to correct config template filename

[bisselch]

Corrected the filename of the config template file.

Pull Request Checklist:

• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Did you make your Pull Request on the dev branch?
• Does your submission pass tests? make test
• Have you lint your code locally prior to submission? make lint
• Could you build and run the docker image successfully? make image
• Could you create a running executable? make executable
• Have you added an explanation of what your changes do and why you'd like to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully ran manual tests with your changes locally?

[Der-Henning]

Hi @opticv.
Thank you for your contribution.