Update to use ArduinoJson 6+ (#1071)

main/ZactuatorPWM.ino

@@ -204,7 +204,7 @@ void MQTTtoPWM(char* topicOri, JsonObject& jsonData) {
     for (int i = 0; i < kNumChannels; ++i) {
       fadeStartValues[i] = currentValues[i];
       JsonVariant value = jsonData[channelJsonKeys[i]];
-      if (value.success()) {
+      if (!value.isNull()) {
         float targetValue = value.as<float>();
         targetValue = min(targetValue, 1.f);
         targetValue = max(targetValue, 0.f);
@@ -219,7 +219,7 @@ void MQTTtoPWM(char* topicOri, JsonObject& jsonData) {
     }
     // ...unless there is a "fade" value in the JSON
     JsonVariant fade = jsonData["fade"];
-    if (fade.success()) {
+    if (!fade.isNull()) {
       // "fade" json value is in seconds. Convert to milliseconds
       long endUpdateTime = currentUpdateTime + (long)(fade.as<float>() * (1000.f));
       // Set the fadeEndUpdateTime for the channels that were modified in the JSON
@@ -236,7 +236,7 @@ void MQTTtoPWM(char* topicOri, JsonObject& jsonData) {
       char key[64];
       snprintf(key, sizeof(key), "gamma-%s", channelJsonKeys[i]);
       JsonVariant value = jsonData[key];
-      if (value.success()) {
+      if (!value.isNull()) {
         float gamma = value.as<float>();
         // Sanity check
         gamma = min(gamma, 4.f);
@@ -245,12 +245,12 @@ void MQTTtoPWM(char* topicOri, JsonObject& jsonData) {
       }
       snprintf(key, sizeof(key), "min-%s", channelJsonKeys[i]);
       value = jsonData[key];
-      if (value.success()) {
+      if (!value.isNull()) {
         calibrationMinLinear[i] = perceptualToLinear(value.as<float>(), i);
       }
       snprintf(key, sizeof(key), "max-%s", channelJsonKeys[i]);
       value = jsonData[key];
-      if (value.success()) {
+      if (!value.isNull()) {
         calibrationMaxLinear[i] = perceptualToLinear(value.as<float>(), i);
       }
     }