anv: update conformanceVersion

The Vulkan CTS started generating the list of valid versions the driver
can report as conformant against based on the active branches, and the
1.3.0 branch we were reporting up to now is no longer valid.

Fixes dEQP-VK.api.driver_properties.conformance_version

Reviewed-by: Mark Janes <markjanes@swizzler.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23784>

src/intel/vulkan/anv_device.c

@@ -1849,7 +1849,7 @@ anv_get_physical_device_properties_1_2(struct anv_physical_device *pdevice,
    p->conformanceVersion = (VkConformanceVersion) {
       .major = 1,
       .minor = 3,
-      .subminor = 0,
+      .subminor = 6,
       .patch = 0,
    };