Add changenote for SIP-disabled support on old CLI versions

Author: angelapwen

CHANGELOG.md

@@ -6,7 +6,7 @@ Note that the only difference between `v2` and `v3` of the CodeQL Action is the
 
 ## [UNRELEASED]
 
-No user facing changes.
+- Workflows running on `macos-latest` using CodeQL CLI versions before v2.15.1 will need to either upgrade their CLI version to v2.15.1 or newer, or change the platform to an Intel MacOS runner, such as `macos-12`. ARM machines with SIP disabled, including the newest `macos-latest` image, are unsupported for CLI versions before 2.15.1. 
 
 ## 3.25.2 - 22 Apr 2024