Bug: equation for max_heat capacity

[KelbijStarDeltares]

In code (esdl_heat_model.py)

    min_heat = capacity * min_fraction_tank_volume
    max_heat = capacity * (1 + min_fraction_tank_volume)
    assert max_heat > 0.0

This must be:

    min_heat = capacity * min_fraction_tank_volume
    max_heat = capacity * (1 **-** min_fraction_tank_volume)
    assert max_heat > 0.0

[KelbijStarDeltares]

Same here:

    # We assume that the height equals the radius of the buffer.
    r = (
        capacity
        * (1 + min_fraction_tank_volume)
        / (self.rho * self.cp * (supply_temperature - return_temperature) * math.pi)
    ) ** (1.0 / 3.0)