Update CONTRIBUTING.md.jinja2, fixing broken link

The previous link was a 404. I think this is the best replacement.

Coordinated issues:

- linkml/linkml-project-cookiecutter#77

template/CONTRIBUTING.md.jinja2

@@ -86,10 +86,10 @@ If you have never editted this ontology before, first follow a [general tutorial
 
 ### How to write great issues?
 
-Please refer to the [OBO Academy best practices](https://oboacademy.github.io/obook/lesson/term-request/).
+Please refer to the [OBO Academy term request guide](https://oboacademy.github.io/obook/howto/term-request/).
 
 <a id="great-pulls"></a>
 
 ### How to create a great pull/merge request?
 
-Please refer to the [OBO Academy best practices](https://oboacademy.github.io/obook/howto/github-create-pull-request/)
+Please refer to the [OBO Academy best practices](https://oboacademy.github.io/obook/howto/github-create-pull-request/)