LipSync now cannot be compiled

[yoshipon]

Describe the bug
Due to the recent change to use M5Unified, the library cannot be compiled with lipSync because it uses M5Core2.

To Reproduce
Compile the programs with lipSync for M5Stack Core2.

m5avatar::Avatar avt;

void setup() {
  ...
  avt.init();
  avt.addTask(m5avatar::lipSync, "lipSync");
}

Logs

In file included from C:\Users\xxx\m5stack-avatar\src/tasks/LipSync.h:10,
                 from C:\Users\yyy\stack_chan_ros\firmware\firmware.ino:9:
C:\Users\xxx\arduino_409486\src/M5Core2.h:138:20: error: conflicting declaration 'M5Core2 M5'
     extern M5Core2 M5;
                    ^~
In file included from C:\Users\yyy\stack_chan_ros\firmware\firmware.ino:1:
C:\Users\xxx\arduino_708812\src/M5Unified.hpp:243:22: note: previous declaration as 'm5::M5Unified M5'
 extern m5::M5Unified M5;

[mongonta0716]

Hi, Thanks for your issue.
This is an omission that was corrected when the library was changed to M5Unified.

Please incorporate the following modifications until the pull request is applied.
#77

[yoshipon]

Thanks for your super fast correction!!