CI: Move to clang-16

As this is now the stable release, move to using that now for our tests.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2a42374..7509a7a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,7 +10,7 @@
 
 # Grab our configured image.  The source for this is found
 # in the u-boot tree at tools/docker/Dockerfile
-image: ${MIRROR_DOCKER}/trini/u-boot-gitlab-ci-runner:jammy-20230308-21Mar2023
+image: ${MIRROR_DOCKER}/trini/u-boot-gitlab-ci-runner:jammy-20230308-04Apr2023
 
 # We run some tests in different order, to catch some failures quicker.
 stages:
@@ -277,7 +277,7 @@
 sandbox with clang test.py:
   variables:
     TEST_PY_BD: "sandbox"
-    OVERRIDE: "-O clang-14"
+    OVERRIDE: "-O clang-16"
   <<: *buildman_and_testpy_dfn
 
 sandbox without LTO test.py: