add wifi reconnection logic

src/sheller.ino

@@ -51,6 +51,15 @@ void setup() {
 }
 
 void loop() {
+  unsigned int wifiRetryCount = 0;
+  if (WiFi.status != WL_CONNECTED){
+    WiFi.reconnect();
+
+    while (WiFi.status != WL_CONNECTED){
+      if (wifiRetryCount++ > 5) return;
+      delay(1000);
+    }
+  }
   if (!client.connected()) {
     reconnect();
   }