Allow percent numbers with decimals in --min-msi and --min-covered-msi

[arudolph-cxt]

Is your feature request related to a problem? Please describe.
We calculate the MSI and mutation coverage manually from the summary log and store the values with 2 decimals. When we add those values to the ci command-line script like so: ... --min-msi=15.77 it fails:
[ERROR] The minimum required MSI percentage should be 15.77%, but actual is 15%. Improve your tests!
Although the actual percentage should be compared with 15.77424023154848% to be exact and therefore pass.

Describe the solution you'd like
The comparison should use float values instead of rounded-down integers to decide if the ci fails.

Describe alternatives you've considered
Rounding down the value to an int, with the drawback of having much less accuracy on bigger projects.

[arudolph-cxt]

According to the code, the flooring seems to be deliberate:

infection/src/Mutant/MetricsCalculator.php

Line 161 in 7894cf5

$detectionRateAll = floor(100 * $defeatedTotal / $this->totalMutantsCount);

Is there a reason for this? Since the values seem to be available as floats, this looks as simple as removing the floor call and ensuring the values are calculated as float and not auto-casted into integer values.
Unless i'm missing something and there was a good reason for this?

This commit seems to be the last change b2a7a2d and i understand why the change from round to floor was done, but why there was actual rounding in the first place seems confusing to me.

[maks-rafalko]

Personally, I don't remember any reasons for rounding. PR is always welcome ;)

[arudolph-cxt]

I'm currently working on one and as expected, two tests fail as they compare against rounded values.

My current approach would be to just use float values instead, a more nuanced approach would be to allow control over the accuracy/decimal amount maybe with a parameter.
I think I can provide a PR shortly.