Update cuda version for 2.x to 12.6

Author: Ruinong Tian

src/config.py

@@ -56,8 +56,8 @@
     2: [
         {
             "build_args": {
-                "TAG_FOR_BASE_MICROMAMBA_IMAGE": "jammy-cuda-12.5.0",
-                "CUDA_MAJOR_MINOR_VERSION": "12.5",  # Should match the previous one.
+                "TAG_FOR_BASE_MICROMAMBA_IMAGE": "jammy-cuda-12.6.0",
+                "CUDA_MAJOR_MINOR_VERSION": "12.6",  # Should match the previous one.
                 "ENV_IN_FILENAME": "gpu.env.in",
                 "PINNED_ENV_IN_FILENAME": "gpu.pinned_env.in",
                 "ARG_BASED_ENV_IN_FILENAME": "gpu.arg_based_env.in",