doc: mention PEP 508 for valid project name

Co-authored-by: Bartosz Sokorski <b.sokorski@gmail.com>
Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

docs/pyproject.md

@@ -17,6 +17,9 @@ The `tool.poetry` section of the `pyproject.toml` file is composed of multiple s
 
 The name of the package. **Required**
 
+This should be a valid name as defined by [PEP 508](https://peps.python.org/pep-0508/#names).
+
+
 ```toml
 name = "my-package"
 ```