Ability to control precision of DataPoints

[percymamedy]

Is your feature request related to a problem? Please describe.
After getting the Points back from Graphite it's rounded to 2 Decimal places

Point {#675 ▼
    #time: Carbon @1574849640 {#676 ▶}
    #value: 0.74
 }

Describe the solution you'd like
It could be cool to have the ability to control the precision when building the Points requests. Maybe a precision method on the Target class or Points class itself.

GraphitePoints::addTarget(Target::make('some.target'))
                        ->precision(4)
                        ->render()

or

$target1 = Target::make('some.target')->precision(2);
$target2 = Target::make('some.target2')->precision(4);

GraphitePoints::addTarget($target1)
                        ->addTarget($target2)
                        ->render()