Update requested SPIR-V Tools version to 1.5

SPV_ENV_Vulkan_1_2 denotes support for all SPIR-V versions that are core
in Vulkan 1.2. This includes 1.4 and 1.5.

Tests: dEQP-VK.*
Bug: b/173046235
Change-Id: I7482d1bff6bf3b2c2291538517f6640647ab644c
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/50670
Tested-by: Sean Risser <srisser@google.com>
Commit-Queue: Sean Risser <srisser@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Vulkan/VkConfig.hpp b/src/Vulkan/VkConfig.hpp
index e5518e8..edcf38c 100644
--- a/src/Vulkan/VkConfig.hpp
+++ b/src/Vulkan/VkConfig.hpp
@@ -27,7 +27,7 @@
 #define SWIFTSHADER_DEVICE_NAME "SwiftShader Device"  // Max length: VK_MAX_PHYSICAL_DEVICE_NAME_SIZE
 #define SWIFTSHADER_UUID "SwiftShaderUUID"            // Max length: VK_UUID_SIZE (16)
 
-const spv_target_env SPIRV_VERSION = SPV_ENV_VULKAN_1_1_SPIRV_1_4;
+const spv_target_env SPIRV_VERSION = SPV_ENV_VULKAN_1_2;
 
 enum
 {