Add minimum toolchains requirements to the documentation

Change-Id: I5c4c6cab8366d8f4959a9edac4b3d9772522a84e
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5578
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/docs/user_guide/errata.dox b/docs/user_guide/errata.dox
index 0c8d684..cca2a39 100644
--- a/docs/user_guide/errata.dox
+++ b/docs/user_guide/errata.dox
@@ -1,5 +1,5 @@
 ///
-/// Copyright (c) 2019-2020 Arm Limited.
+/// Copyright (c) 2019-2021 Arm Limited.
 ///
 /// SPDX-License-Identifier: MIT
 ///