Bump minimum clang version to 6.13

Clang 6.12 in Debug mode can cause a stack overflow on PSoC platform.
Rather than increasing the stack size, bump the minimum clang version.

Change-Id: I0689a759495c1a8428d7a140277588836c7fdeae
Signed-off-by: Chris Brand <chris.brand@cypress.com>
diff --git a/docs/getting_started/tfm_getting_started.rst b/docs/getting_started/tfm_getting_started.rst
index bd2934d..b9a620e 100644
--- a/docs/getting_started/tfm_getting_started.rst
+++ b/docs/getting_started/tfm_getting_started.rst
@@ -153,7 +153,7 @@
 be available in the build environment. The currently supported compiler
 versions are:
 
-    - Arm Compiler v6.10.1 ~ v6.14, v6.18+
+    - Arm Compiler v6.13 ~ v6.14, v6.18+
 
       .. tabs::
 
@@ -463,3 +463,5 @@
 --------------
 
 *Copyright (c) 2017-2022, Arm Limited. All rights reserved.*
+*Copyright (c) 2022 Cypress Semiconductor Corporation (an Infineon company)
+or an affiliate of Cypress Semiconductor Corporation. All rights reserved.*