update pyjulip instructions.

Author: wcwitt

docs/src/gettingstarted/installation.md

@@ -31,6 +31,10 @@ pkg"activate pathtoproject"
 
 ### Setting up the Python ASE calculator
 
+!!! warning
+    At present, it is necessary to have `ASE`, `JuLIP` and `ACE1` installed in your Julia project to use `pyjulip`.
+
+
 We use a wrapper called `pyjulip` to call julia and evaluate ACE potentials. In a terminal, with the correct julia project and python environment selected, run the following code:
 
 ```