codeowners: add ownership of zdnn backend [no ci] (#16232)

add @Andreas-Krebbel to owners of zDNN backend

Signed-off-by: Aaron Teo <aaron.teo1@ibm.com>

CODEOWNERS

@@ -63,7 +63,7 @@
 /ggml/src/ggml-quants.*                 @ggerganov
 /ggml/src/ggml-threading.*              @ggerganov @slaren
 /ggml/src/ggml-vulkan/                  @0cc4m
-/ggml/src/ggml-zdnn/                    @taronaeo @AlekseiNikiforovIBM
+/ggml/src/ggml-zdnn/                    @taronaeo @Andreas-Krebbel @AlekseiNikiforovIBM
 /ggml/src/ggml.c                        @ggerganov @slaren
 /ggml/src/ggml.cpp                      @ggerganov @slaren
 /ggml/src/gguf.cpp                      @JohannesGaessler @Green-Sky