Add M5Unit-HEART

[TinyuZhao]

No description provided.

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/m5stack/M5Unit-HEART:

Linting library in M5Unit-HEART
INFO: No header file found matching library name (M5Unit-HEART.h). Best practices are for primary header filename to    
      match library name.                                                                                               
      See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format            
      (Rule LS008)                                                                                                      
WARNING: library.properties depends field item(s) M5UnitUnified, M5Utility, M5HAL not found in the Library Manager      
         index.                                                                                                         
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format         
         (Rule LP048)                                                                                                   

Linter results for project: 0 ERRORS, 1 WARNINGS

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Linting sketch in M5Unit-HEART/examples/UnitUnified/PlotToSerial

Linter results for project: no errors or warnings

-------------------

Linter results for projects: 0 ERRORS, 1 WARNINGS

[github-actions]

Your submission has now been accepted! Thanks for your contribution to the Arduino Library Manager index.

The library(s) will be available for installation via Library Manager within a day's time.

You can check the logs from the Library Manager indexer for your library(s) here:
http://downloads.arduino.cc/libraries/logs/github.com/m5stack/M5Unit-HEART/