Restructure build targets of CMake configuration

* Rename the library under test from src to GildedRoseLib.
* Move the lib folder to test/third_party and handle ApprovalTests.hpp as header-only dependency.
* Remove the superfluous googletest_approval_main.cpp (in the same sense as there is only one GildedRoseCatch2ApprovalTests.cc)
* Set USE_FOLDERS property such that target ALL_BUILD, RUN_TESTS and ZERO_CHECK are grouped for Visual Studio.
* Set WORKING_DIRECTORY such that the RUN_TESTS target works successfully.
* Fix C++ language standard for Catch2 v3 to C++14.
* Bump third-party dependencies
  * Update ApprovalTests.hpp to v10.13.0
  * Update Catch2 to v3.8.0
  * Update GTest to v1.16.0

cpp/test/cpp_catch2_unittest/CMakeLists.txt

@@ -1,9 +1,13 @@
 set(TEST_NAME GildedRoseCatch2UnitTests)
 add_executable(${TEST_NAME})
 target_sources(${TEST_NAME} PRIVATE GildedRoseCatch2UnitTests.cc)
-target_link_libraries(${TEST_NAME} lib src Catch2::Catch2 Catch2::Catch2WithMain )
-set_property(TARGET ${TEST_NAME} PROPERTY CXX_STANDARD 11)
-add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME})
+target_link_libraries(${TEST_NAME} GildedRoseLib Catch2::Catch2 Catch2::Catch2WithMain )
+set_property(TARGET ${TEST_NAME} PROPERTY CXX_STANDARD 14)
+add_test(
+    NAME ${TEST_NAME}
+    COMMAND ${TEST_NAME}
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+)
 
 # Set compiler option /FC for Visual Studio to to make the __FILE__ macro expand to full path. 
 # The __FILE__ macro is used by Catch2 to get the path to current test file.

cpp/test/cpp_catch2_unittest/GildedRoseCatch2UnitTests.cc

@@ -1,5 +1,4 @@
-#define CATCH_CONFIG_MAIN  // This tells Catch to provide a main() - only do this in one cpp file
-#include "catch2/catch_all.hpp"
+#include <catch2/catch_all.hpp>
 #include "GildedRose.h"
 
 TEST_CASE("GildedRoseUnitTest", "Foo")