refactor: add HasSetUpTearDown concept

Author: daantimmer

cucumber_cpp/library/Body.hpp

@@ -2,6 +2,7 @@
 #define CUCUMBER_CPP_BODY_HPP
 
 #include <any>
+#include <concepts>
 #include <string>
 #include <variant>
 #include <vector>
@@ -15,7 +16,14 @@ namespace cucumber_cpp::library
         virtual void Execute(const std::variant<std::vector<std::string>, std::vector<std::any>>& args = {}) = 0;
     };
 
-    template<class T>
+    template<typename T>
+    concept HasSetUpTearDown =
+        requires(T t) {
+            { t.SetUp() } -> std::convertible_to<void>;
+            { t.TearDown() } -> std::convertible_to<void>;
+        };
+
+    template<HasSetUpTearDown T>
     struct SetUpTearDownWrapper
     {
         explicit SetUpTearDownWrapper(T& t)