Add support for dual heaters/temperature range

[pickanothername]

Is your feature request related to a problem? Please describe: When trying to use "auto" mode (which will heat OR cool depending on the ambient temperature), it is impossible to set a temperature range.

Describe the solution you'd like: Ability to set a minimum and maximum temperature range; currently they are locked to the same number.

Describe alternatives you've considered: In this case, I don't believe an alternative is warranted.

Additional context: Screenshot of the issue:

Minimum and maximum temperatures are inseparable

Screenshot of expected behavior (using a different thermostat, obviously):

Minimum and maximum temperatures are seperated

[eibenp]

This is a limitation of GREE AC units. They do not accept temperature ranges in Auto mode. The Home App behavior is in sync with the device capabilities.