Clarify installing most recent version

SamProkopchuk · SamProkopchuk · commit 0ce3043ec6a2 · 2022-07-11T10:50:39.000-04:00
diff --git a/doc/source/usage.rst b/doc/source/usage.rst
@@ -17,6 +17,12 @@ Using the ``pip`` CLI:
 
    $ pip install skillsnetwork
 
+To upgrade or ensure the most recent version is installed:
+
+.. code-block:: console
+
+   $ pip install -U skillsnetwork
+
 JupyterLite
 +++++++++++
 
