Update README.md

Jason2866 · web-flow · commit 7f5765b7b8e8 · 2024-12-17T10:13:09.000+01:00
diff --git a/README.md b/README.md
@@ -30,7 +30,7 @@ board = ...
 ```
 
 ### Development version
-espressif Arduino repo branch master and latest compiled Arduino libs
+espressif Arduino repo branch release/v3.1.x and latest compiled Arduino libs
 
 ```ini
 [env:development]
