Pablo Correa Gomez authored Jun 17, 2021 and Bastien Nocera committed Jun 30, 2021

Before, the low level for changing the battery icon was hardcoded.
However, as the `low_percentage` property is settable by the user using
`PercentageLow` option. That can lead to inconsistencies when PercentageLow
is not the default. For example, if PercentageLow is set higher than 10,
the Low Battery level warning will be sent at the user-set level, but the
battery icon would not be updated to "caution" until the percentage
drops below 10%.

This issue is solved in this commit by using the `low_percentage` property
for the comparison instead of hardcoding the default.