Bump GTEST version to the newest in our testing

Author: lukaszstolarczuk

test/CMakeLists.txt

@@ -9,7 +9,7 @@ include(FetchContent)
 FetchContent_Declare(
     googletest
     GIT_REPOSITORY https://github.com/google/googletest.git
-    GIT_TAG release-1.12.1)
+    GIT_TAG v1.15.2)
 
 # For Windows: Prevent overriding the parent project's compiler/linker settings
 set(gtest_force_shared_crt