Replace Catch header by a xmake package

tests/xmake.lua

@@ -3,11 +3,15 @@ if is_mode("asan") then
 	add_defines("CATCH_CONFIG_NO_POSIX_SIGNALS")
 end
 
+add_requires("catch2")
+
 target("NazaraClientUnitTests")
 	set_group("Tests")
 	set_kind("binary")
 
 	add_deps("NazaraClientSDK")
+	add_packages("catch2")
+
 	add_files("main_client.cpp")
 	add_files("resources.cpp")
 	add_files("Engine/**.cpp")
@@ -17,6 +21,8 @@ target("NazaraUnitTests")
 	set_kind("binary")
 
 	add_deps("NazaraSDK")
+	add_packages("catch2")
+
 	add_files("main.cpp")
 	add_files("resources.cpp")
 	add_files("Engine/**.cpp")