Update GTEST version (#68)

tests/unit_tests/CMakeLists.txt

@@ -174,7 +174,7 @@ FetchContent_Declare(
     googletest
     PREFIX extern/googletest
     GIT_REPOSITORY https://github.com/google/googletest.git
-    GIT_TAG release-1.10.0
+    GIT_TAG release-1.12.0
 )
 
 set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)