Update CHANGELOG.md

Author: coadaflorin

csharp/ql/lib/CHANGELOG.md

@@ -68,7 +68,6 @@
 
 ### Minor Analysis Improvements
 
-* .NET 9 is now required to build the C# extractor.
 * The Models as Data models for .NET 8 Runtime now include generated models for higher order methods.
 
 ## 3.1.0