fix install path

Author: ptonner

docs/index.rst

@@ -20,7 +20,7 @@ Installation
 LANTERN currently must be installed from source. It is recommended to
 install in a virtual environment (e.g. venv or conda)::
 
-  python -m pip install git+https://github.com/ptonner/lantern.git@XXX
+  python -m pip install git+https://github.com/usnistgov/lantern.git
 
 Quickstart
 ==========