Update CHANGELOG.md

Author: lzchen

CHANGELOG.md

@@ -11,7 +11,7 @@
 - Add support for Urllib3/Urllib instrumentation
     ([#256](https://github.com/microsoft/ApplicationInsights-Python/pull/256))
 - Change instrumentation config to use TypedDict InstrumentationConfig
-    ([#257](https://github.com/microsoft/ApplicationInsights-Python/pull/257))
+    ([#259](https://github.com/microsoft/ApplicationInsights-Python/pull/259))
 
 ## [1.0.0b10](https://github.com/microsoft/ApplicationInsights-Python/releases/tag/v1.0.0b10) - 2023-02-23