docs: install from test pypi

Author: lukasberbuer

docs/python/get-started.md

@@ -2,12 +2,16 @@
 
 ## Install
 
-The Python library can be easily installed with [PyPI](https://pypi.org/project/openae/):
+The Python library can be easily installed with `pip`:
 
 ```shell
-$ pip install openae
+$ pip install -i https://test.pypi.org/simple/ openae
 ```
 
+:::{important}
+The package is currently hosted ony on [Test PyPI](https://test.pypi.org) due to naming policy conflicts. We are trying to claim the project name `openae` for PyPI [here](https://github.com/pypi/support/issues/5968). Hopefully, we can install the package with `pip install openae` from PyPI soon.
+:::
+
 ## Minimal example
 
 ```{literalinclude} ../../bindings/python/examples/features_minimal.py