Correct mount path /usr/local/lib/python3.12

Author: jennydaman

Diff for: README.md

@@ -128,7 +128,7 @@ Mount the source code `app.py` into a container to try out changes without rebui
 
 ```shell
 docker run --rm -it --userns=host -u $(id -u):$(id -g) \
-    -v $PWD/app.py:/usr/local/lib/python3.11/site-packages/app.py:ro \
+    -v $PWD/app.py:/usr/local/lib/python3.12/site-packages/app.py:ro \
     -v $PWD/in:/incoming:ro -v $PWD/out:/outgoing:rw -w /outgoing \
     localhost/fnndsc/pl-appname commandname /incoming /outgoing
 ```