Remove fatalized warnings

[zakame]

Do not use warnings FATAL => 'all' per https://perldoc.pl/warnings#Fatal-Warnings

[codecov-io]

Codecov Report

Merging #18 into master will decrease coverage by 0.67%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #18      +/-   ##
==========================================
- Coverage   94.63%   93.95%   -0.68%     
==========================================
  Files           4        4              
  Lines         149      149              
  Branches       22       22              
==========================================
- Hits          141      140       -1     
- Misses          0        1       +1     
  Partials        8        8

Impacted Files	Coverage Δ
lib/Math/Function/Interpolator/Linear.pm	95% <100%> (ø)	⬆️
lib/Math/Function/Interpolator/Quadratic.pm	89.47% <100%> (ø)	⬆️
lib/Math/Function/Interpolator.pm	92.3% <100%> (ø)	⬆️
lib/Math/Function/Interpolator/Cubic.pm	96.55% <100%> (-1.73%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update df848b9...9250fb9. Read the comment docs.