Firmware doesn't compile due to invalid call to `RPC_subscribe()`

[dmohns]

Compiling the firmware fails with

/Users/d.mohns/Development/OpenSmartMeter/Firmware code/smart_energy_meter/smart_energy_meter.ino:827:7: error: 'using ThingsBoard = class ThingsBoardSized<>' {aka 'class ThingsBoardSized<>'} has no member named 'RPC_subscribe'; did you mean 'RPC_Subscribe'?
  827 |    tb.RPC_subscribe();
      |       ^~~~~~~~~~~~~
      |       RPC_Subscribe

Note the different capitalisation of the S.

Commenting out that line makes the firmware compile.

[dmohns]

For we commented out the line in here: #17

But should probably bring it back 😉

[dmohns]

In the original version that was confirmed working, the following line was added to ThingsBoard-0.6.0/src/ThingsBoard.h

	inline bool RPC_subscribe() {
      //ThingsBoardSized::m_subscribedInstance = NULL;
      return m_client.subscribe("v1/devices/me/rpc/request/+");
    }