chore: minor update in contribution guidelines

- suggest the use of conventional commits
- update location of mocked responses for tests

Author: mthh

CONTRIBUTING.md

@@ -37,7 +37,8 @@ When contributing, we expect you to:
 - close an existing issue. If there is none yet for your fix, please [create one](https://github.com/gis-ops/routingpy/issues/new).
 - write/adapt unit tests and/or mock API tests, depending on the introduced or fixed functionality
 - limit the number of commits to a minimum, i.e. responsible use of [`git commit --amend [--no-edit]`](https://www.atlassian.com/git/tutorials/rewriting-history#git-commit--amend)
-- use meaningful commit messages, e.g. `commit -m "[bugfix] heremaps used [lat, long] as locations input parameter"`
+- use meaningful commit messages (and ideally follow the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/)
+  specification), e.g. `commit -m "fix: heremaps used [lat, long] as locations input parameter"`
 - you can branch off `master` and put a PR against `master` as well
 
 ### Setup
@@ -77,7 +78,7 @@ pre-commit install
 
 We only do mocked tests as routing results heavily depend on underlying data, which, at least in the case of the FOSS routing
 engines, changes on a very regular basis due to OpenStreetMap updates. All queries and most mocked responses are located in
-`test/test_helper.py` in `dict`s. This unfortunately also means, that our tests are less API tests and more unit tests and can't catch
+`test/data/mock.py` in `dict`s. This unfortunately also means, that our tests are less API tests and more unit tests and can't catch
 updates on providers' API changes.
 
 ```bash