CI: update clang compiler to version 20

closes: #15416

Signed-off-by: Philip H <47042125+pheiduck@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 46eda8d..edad08a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,7 +22,7 @@
     env:
       CC: ${{ matrix.compiler }}
       GCC_VER: 13
-      CLANG_VER: 18
+      CLANG_VER: 19
       TEST: test
       SRCDIR: ./src
       LEAK_CFLAGS: -DEXITFREE