Fix car door lock status

[CM000n]

I happened to notice today that the current approach for determining locked doors returns None for unlocked doors.
Toyota's API handles these things really strangely. 😕
Instead of setting the values for carstatus_locked to True and False accordingly, a separate carstatus_unlocked value is passed for unlocked doors.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (6e651ed) 72.46% compared to head (0d904d7) 72.47%.

Files	Patch %	Lines
mytoyota/models/lock_status.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #272   +/-   ##
=======================================
  Coverage   72.46%   72.47%           
=======================================
  Files          28       28           
  Lines        1351     1355    +4     
=======================================
+ Hits          979      982    +3     
- Misses        372      373    +1     

Flag	Coverage Δ
unittests	72.47% <80.00%> (+<0.01%)	⬆️

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