Check for the Catch2 CMake file instead of the entire directory

CMakeLists.txt

@@ -16,7 +16,7 @@ add_custom_target(check
 # Specify the .cpp files for the executables
 add_executable(ecss_services src/main.cpp src/Message.cpp src/Service.cpp src/Services/TestService.cpp)
 
-IF(EXISTS lib/Catch2)
+IF(EXISTS lib/Catch2/CMakeLists.txt)
 add_subdirectory(lib/Catch2)
 add_executable(tests src/Message.cpp src/Service.cpp src/Services/TestService.cpp tests/tests.cpp tests/Message.cpp)
 target_link_libraries(tests Catch2::Catch2)