feat: add Convert

[ccoVeille]

This PR improves the issues @ldemailly had with its implementation

Fixes #21

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 35 lines in your changes missing coverage. Please review.

Project coverage is 80.97%. Comparing base (390ade6) to head (8749dd5).
Report is 18 commits behind head on main.

Files with missing lines	Patch %	Lines
generics.go	50.00%	34 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              main      #33       +/-   ##
============================================
- Coverage   100.00%   80.97%   -19.03%     
============================================
  Files            3        4        +1     
  Lines          114      184       +70     
============================================
+ Hits           114      149       +35     
- Misses           0       34       +34     
- Partials         0        1        +1     

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[ccoVeille]

draft as the coverage is still low while I added so a lot of tests... I quit for the day

[ldemailly]

Can you share which of the test would fail with my version?

Also you shouldn't math.Trunc() inside convert. Doing

f := 1.5
v, err := Convert[int](f)

should error as it definitively does lose precision

That's why my version has Truncate() and Round() but also let you check "direct" floats if the expectations is that they are supposed to have already been made into integers

Edit: see TestNonIntegerFloat in fortio/safecast#8

[ccoVeille]

Replaced by #55