Make GIF example use static const array

Author: earlephilhower

libraries/ESP8266WebServer/examples/HelloServer/HelloServer.ino

@@ -68,7 +68,7 @@ void setup(void) {
   });
 
   server.on("/gif", []() {
-    uint8_t gif[] = {
+    static const uint8_t gif[] = {
       0x47, 0x49, 0x46, 0x38, 0x37, 0x61, 0x10, 0x00, 0x10, 0x00, 0x80, 0x01,
       0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0x2c, 0x00, 0x00, 0x00, 0x00,
       0x10, 0x00, 0x10, 0x00, 0x00, 0x02, 0x19, 0x8c, 0x8f, 0xa9, 0xcb, 0x9d,