use logo from logo repo in readme

Author: tomeichlersmith

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-    <img src="https://github.com/LDMX-Software/ldmx-software.github.io/blob/trunk/src/img/ldmx_logo_dark.png" width="500">
+    <img src="https://github.com/LDMX-Software/logo/releases/download/2025.05.22/ldmx-sw.png" width="500">
 </p>
 
 <p align="center">