Merge pull request flairNLP#489 from flairNLP/update-documentation-wi…

…th-known-issues

Add section about known issues to documentation

docs/how_to_contribute.md

@@ -29,6 +29,13 @@ If you haven't done this yet or are uncertain, follow these steps:
 3. Navigate to the root of the repository.
 4. Run `pip install -e .[dev]`
 
+## Known issues:
+
+1. `zsh: no matches found: .[dev]`
+When using zsh, you have to wrap the optional dependencies in quotes like this: `pip install -e .'[dev]'`.
+See [this issue](https://github.com/mu-editor/mu/issues/852#issue-451861103) for further information.
+
+
 # Contribution tutorials
 
 1. [How to add a publisher](how_to_add_a_publisher.md)