Update TF version in Cross compilation guide

Signed-off-by: Nikhil Raj <nikhil.raj@arm.com>
Change-Id: Ic8efc05bfea3ac007aec03b0b6d3edd3a9e18819
diff --git a/BuildGuideCrossCompilation.md b/BuildGuideCrossCompilation.md
index 9f05ad5..2b94ff6 100644
--- a/BuildGuideCrossCompilation.md
+++ b/BuildGuideCrossCompilation.md
@@ -122,11 +122,11 @@
         ```
 
 #### <a name="buildtf">Build Tensorflow</a>
-* Building Tensorflow version 1.15:
+* Building Tensorflow version 2.3.1:
     ```bash
     git clone https://github.com/tensorflow/tensorflow.git
     cd tensorflow/
-    git checkout 590d6eef7e91a6a7392c8ffffb7b58f2e0c8bc6b
+    git checkout fcc4b966f1265f466e82617020af93670141b009
     ../armnn/scripts/generate_tensorflow_protobuf.sh ../tensorflow-protobuf ../google/x86_64_pb_install
     ```