Return minimum of series and other, element-wise (binary operator div).
**parameter:** {other} Series, Numbers to check minimum against
**return:** {Series}
Example
let data1 = [30, 40, 3, 5]
let data2 = [10, 41, 2]
let sf1 = new Series(data1)
let sf2 = new Series(data2)
sf1.minimum(sf2)