Docs.

docs/raspberry_pi.md

@@ -18,3 +18,7 @@ with `poetry add rlai`) or as a submodule as shown in the cart-pole system descr
 4. Install the project.
 Note that RLAI depends on Qt6 for graphical rendering of certain simulations and plots. These renderings will not be 
 possible on the Pi, since Qt6 isn't installed.
+5. If poetry installations hang, you might require the following:
+   ```shell
+   export PYTHON_KEYRING_BACKEND=keyring.backends.fail.Keyring
+   ```