Doc/releases/coreboot-4.21: Update toolchain section

Change-Id: Ie153212a6efa98d7a8942097a1d263837510074d
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76391
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
diff --git a/Documentation/releases/coreboot-4.21-relnotes.md b/Documentation/releases/coreboot-4.21-relnotes.md
index 82e30ab..623930c 100644
--- a/Documentation/releases/coreboot-4.21-relnotes.md
+++ b/Documentation/releases/coreboot-4.21-relnotes.md
@@ -22,10 +22,11 @@
 
 ### Toolchain updates
 
-* Upgrade IASL from 20221020 to 20230331
-* Upgrade LLVM from 15.0.7 to 16.0.5
-* Upgrade nasm from 2.15.05 to 2.16.01
+* Upgrade IASL from 20221020 to 20230628
+* Upgrade LLVM from 15.0.7 to 16.0.6
+* Upgrade NASM from 2.15.05 to 2.16.01
 * Upgrade CMake from 3.26.3 to 3.26.4
+* Upgrade GCC from 11.3.0 to 11.4.0
 
 Additional coreboot changes
 ---------------------------