round real value with 2 decimal on server sync data json

src/AirGradient.cpp

@@ -36,3 +36,7 @@ int AirGradient::getI2cSclPin(void) {
 String AirGradient::getVersion(void) { return AG_LIB_VER; }
 
 BoardType AirGradient::getBoardType(void) { return boardType; }
+
+double AirGradient::round2(double value) {
+  return (int)(value * 100 + 0.5) / 100.0;
+}

src/AirGradient.h

@@ -107,6 +107,14 @@ public:
    */
   String getVersion(void);
 
+  /**
+   * @brief Round double value with for 2 decimal
+   * 
+   * @param valuem Round value
+   * @return double 
+   */
+  double round2(double value);
+
 private:
   BoardType boardType;
 };