(0.1).pow(20) == 0

[safinaskar]

@davidli2010 , in yashan-technologies/decimal-rs#6 you told me that pgnumeric has "up to 1000 digits of precision". But it seems this is not true. Consider this code:

    use pgnumeric::NumericBuf;
    let a: NumericBuf = "0.1".parse::<NumericBuf>().unwrap().pow("20".parse::<NumericBuf>().unwrap().as_numeric()).unwrap();
    assert!(a > "0".parse::<NumericBuf>().unwrap());

I use pgnumeric 0.2.1. I think this code should run successfully. But assertion fails. I. e. pgnumeric thinks that 0.1 ^ 20 > 0 is not true