Fix passing different types to std::min in cost_functions.hpp (#3244)

Author: traversaro

moveit_planners/stomp/include/stomp_moveit/cost_functions.hpp

@@ -168,7 +168,7 @@ CostFn getCostFunctionFromStateValidator(const StateValidatorFn& state_validator
       const long kernel_start = mu - static_cast<long>(sigma) * 4;
       const long kernel_end = mu + static_cast<long>(sigma) * 4;
       const long bounded_kernel_start = std::max(0l, kernel_start);
-      const long bounded_kernel_end = std::min(values.cols() - 1, kernel_end);
+      const long bounded_kernel_end = std::min(static_cast<long>(values.cols()) - 1, kernel_end);
       for (auto j = bounded_kernel_start; j <= bounded_kernel_end; ++j)
       {
         costs(j) = std::exp(-std::pow(j - mu, 2) / (2 * std::pow(sigma, 2))) / (sigma * std::sqrt(2 * M_PI));