update README.md

Author: kramerqk

README.md

@@ -1,7 +1,7 @@
 <!-- Currently entirely Copilot-generated -->
 # RTEST: Real Time Electronic Structure Theory
 
-<img src="./favicon.ico" width="50">
+<img src="web/favicon.ico" width="50">
 
 ## Code Check
 ![Ruff Code Check](https://github.com/kramerqk/tdhf_proto/actions/workflows/ruff.yml/badge.svg)