replace & with oxford comma

Author: bitterpanda63

README.md

@@ -60,7 +60,7 @@ Zen instruments the following AI SDKs to track which models are used and how man
 * ✅ [`anthropic`](https://pypi.org/project/anthropic/)
 * ✅ [`mistralai`](https://pypi.org/project/mistralai) ^1.0.0
 
-Zen is compatible with Python 3.8-3.13 and can run on Windows, Linux & Mac OS X.
+Zen is compatible with Python 3.8-3.13 and can run on Windows, Linux, and Mac OS X.
 
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