Change c++17 to c++20. Fixed formatting on assignment from double.

MString.cpp

@@ -3,6 +3,7 @@
 #include "uuid/uuid.h"
 #include <cstring>
 #include <string>
+#include <format>
 #include <iomanip>
 #include <stdlib.h>
 
@@ -83,10 +84,12 @@ namespace coreutils {
    }
 
    MString::MString(double value) {
-      std::string data = std::to_string(value);
-      setSize(data.length());
-      memcpy(this->data, (char *)data.c_str(), data.length());
-      cursor = this->data;      
+      std::stringstream temp;
+      temp << std::format("{}", value);
+      std::string temp2 = temp.str();
+      setSize(temp2.length());
+      memcpy(this->data, (char *)temp2.data(), temp2.length());
+      cursor = this->data;
    }
    
    MString::~MString() {
@@ -130,9 +133,11 @@ namespace coreutils {
    }
 
    MString &MString::operator=(double value) {
-      std::string data = std::to_string(value);
-      setSize(data.length());
-      memcpy(this->data, (char *)data.c_str(), data.length());
+      std::stringstream temp;
+      temp << std::format("{}", value);
+      std::string temp2 = temp.str();
+      setSize(temp2.length());
+      memcpy(this->data, (char *)temp2.data(), temp2.length());
       cursor = this->data;
       return *this;
    }