Docs: Fix release version in build instructions

Change-Id: I45343af0e1413bae893353992d2a3facd2e1eb80
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/docs/building/tfm_build_instruction.rst b/docs/building/tfm_build_instruction.rst
index 59e93c6..db2ab89 100644
--- a/docs/building/tfm_build_instruction.rst
+++ b/docs/building/tfm_build_instruction.rst
@@ -3,7 +3,7 @@
 ##################
 
 .. warning::
-    The build process was changed a lot in Q3 2023 and included into the release after v1.9.
+    The build process was changed a lot in Q3 2023 and included into the release v2.0.
     For building instructions for early versions please refer to the documentation of respective
     versions.