message: Fix links for PR templates
diff: Thank you for contributing to harp.gl!
  Before requesting a pull request, please remember to check the following documents:
  -* [contribution guidelines](../CONTRIBUTING.md)
  -* [coding style](../CODINGSTYLE.md)
  +* [contribution guidelines](https://github.com/heremaps/harp.gl/blob/master/CONTRIBUTING.md)
  +* [coding style](https://github.com/heremaps/harp.gl/blob/master/CODINGSTYLE.md)
  If you are adding new functionality we would highly appreciate if you can describe what is the capability you are adding and even better if you can add some examples. Please also remember to add tests for it.
  