Remove nightly requirement for no_std

[Dicklessgreat]

I think it is overkill that all dasp libraries require Nightly just because there is no sqrt() function implementation for floating point types in no_std environment.
In my case, I just wanted to use the Frame type, but compiler requires nightly.
I did the same implementation to the sqrt() method as micromath or this one that it was based on.
https://github.com/tarcieri/micromath/blob/6de9df6943b6f06c087ab43ddc3523a379e00369/src/float/sqrt.rs#L13
https://bits.stephan-brumme.com/squareRoot.html
Adding micro_math to dependencies is a good idea, but if you think it is overkill, how about what I wrote?
What I wrote is just a suggestion, I believe the issue is that dasp requires Nightly if you try to use it in no_std.

[roderickvd]

This broke the CI and causes RMS values to be way off on no_std. Please consider PR #192 that fixes both.