Minimum and maximum values config policy rules for int/floats crash plugins when used

[IRCody]

Adding either

cpolicy.NewIntegerRule("crashes", false, 0, 1, 2) 

or

cpolicy.NewFloatRule("crashes", false, 0, 1, 2)

to a plugins GetConfigPolicy method will cause the plugin to crash on startup. This is because the min/max values are not handled properly here and here. The failing logic for both is:

    options := make([]*int, 1)
    for i, o := range opts {
        options[i] = &o
    }

    return &IntRule{
        key:      key,
        required: req,
        default_: options[0],
    }, nil

This causes a crash because, in the case where len(opts) is greater than 1 (i.e. if a min or max is set), it will cause out of bounds error on options since it's statically size 1. A second issue is that the minimum/maximum are never set in the returned rule.