[PR] Add is_valid_url? function

[LuchoTurtle]

closes #64

This is a quick merge. Found this useful for small Elixir projects, thanks @ndrean 👌

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (335303d) to head (f329075).
⚠️ Report is 30 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #68   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files            1         1           
  Lines           50        52    +2     
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+ Hits            50        52    +2     

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[nelsonic]

Agree that checking the validity of a URL is useful. ✅
Just have a quick question in the issue: #64 (comment) ❓

If you need this function immeditately, please see: https://hexdocs.pm/link/Link.html#valid?/1
https://github.com/dwyl/link/blob/ca72089c0a56a0e1a96360ccba424b49b8165e3b/lib/link.ex#L143-L161 💭