Add integral and floating point constraints

dune/common/std/cmath.hh

@@ -36,7 +36,8 @@ namespace Dune
         }
 
         template <class T>
-        T sqrt(T t)
+        constexpr auto sqrt(T t)
+        requires (std::is_floating_point_v<T> || std::is_integral_v<T>)
         {
             using std::sqrt;
             // backport between C++20 and C++26