Updated README for CPU arch note

When building Spring AI, there is a dependecy on PyTorch which is
dependent upon the CPU architecture of the machine it is running on. In
MacOS, an x86 built JVM can run on an ARM processor due to Rosetta.
However, this arrangement will result in the project attempting to get
the x86 distribution of PyTorch which will not run on an ARM processor.
This note is to clarify how to validate if your JDK is reporting the
correct CPU architecture your machine is actually running.

Auto-cherry-pick to 1.1.x

Signed-off-by: Michael Minella <michael.minella@broadcom.com>

Author: mminella

README.md

@@ -74,6 +74,8 @@ To clone it you have to either:
 The project targets and build artifacts compatible with Java 17+, but requires JDK 21
 to build. This is enforced by the maven enforcer plugin.
 
+**NOTE:** Building Spring AI requires components that depend on your specific CPU architecture (PyTorch for example). MacOS can seamlessly run x86 Java applications on ARM processors using Rosetta, but this will fail when building this project because it tries to download architecture-specific native dependencies. (Note: this is only an issue for building the project, not for consuming the libraries). If you are unsure if you have the correct JDK distribution for your CPU, run the command `java -XshowSettings:properties -version 2>&1 | grep os.arch` from a fresh terminal to validate that it matches your machine.
+
 To build with running unit tests
 
 ```shell