Update README to indicate CMake is added

Author: LandryNorris

README.md

@@ -11,7 +11,8 @@ Using
 -----
 
 This image contains the STM32CubeCLT package (located at /opt/st) and is based on
-Ubuntu 24.04. To use the package, pull `ghcr.io/revrobotics/stm32cubeclt:<version>`.
+Ubuntu 24.04 with CMake installed using KitWare's APT repository. To use the package, 
+pull `ghcr.io/revrobotics/stm32cubeclt:<version>`.
 
 Building
 --------