Fix validation warning in descriptorindexing example

examples/descriptorindexing/descriptorindexing.cpp

@@ -56,6 +56,7 @@ class VulkanExample : public VulkanExampleBase
 
 		// [POI] Enable required extensions
 		enabledInstanceExtensions.push_back(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME);
+		enabledDeviceExtensions.push_back(VK_KHR_MAINTENANCE1_EXTENSION_NAME);
 		enabledDeviceExtensions.push_back(VK_KHR_MAINTENANCE3_EXTENSION_NAME);
 		enabledDeviceExtensions.push_back(VK_EXT_DESCRIPTOR_INDEXING_EXTENSION_NAME);