[CI] Bump IGC version (#16635)

We are currently using `24.52.32224.5` and the corresponding IGC version
is v.2.5.6 as per
[here](https://github.com/intel/compute-runtime/releases/tag/24.52.32224.5).
The script doesn't update it, I'll fix it tomorrow but for now just
manually bump it.

Signed-off-by: Sarnie, Nick <nick.sarnie@intel.com>

Author: sarnex

devops/dependencies.json

@@ -7,9 +7,9 @@
       "root": "{DEPS_ROOT}/opencl/runtime/linux/oclgpu"
     },
     "igc": {
-      "github_tag": "v2.2.3",
-      "version": "2.2.3",
-      "url": "https://github.com/intel/intel-graphics-compiler/releases/tag/v2.2.3",
+      "github_tag": "v2.5.6",
+      "version": "2.5.6",
+      "url": "https://github.com/intel/intel-graphics-compiler/releases/tag/v2.5.6",
       "root": "{DEPS_ROOT}/opencl/runtime/linux/oclgpu"
     },
     "cm": {