Fix for isFQDN wth numeric domain names

[tux-tn]

Hello

• This PR fixes isFQDN returns false for a valid FQDN #1545 Validator 13.5.1 doesn't support 163/126 format email #1543 and Regression 13.5.1: isURL() fails for number urls, e.g. 1234.com #1544
• I refactored isFQDN a little to prevent having multiple loops and fixed the issue with numeric domain names
• I added test cases to isFQDN, isURL and isEmail to prevent having the same issue in the future

Checklist

• PR contains only changes related; no stray files, etc.
• Tests written (where applicable)

[codecov]

Codecov Report

Merging #1546 (b35b1f8) into master (302d295) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1546   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           99        99           
  Lines         1773      1773           
=========================================
  Hits          1773      1773           

Impacted Files	Coverage Δ
src/lib/isFQDN.js	100.00% <100.00%> (ø)

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[profnandaa]

Fixes #1543

[profnandaa]

LGTM, thanks for the fix!

[niftylettuce]

Can we get a release out to npm? @profnandaa

[profnandaa]

13.5.2 is now published on NPM as hotfix. Here is the hotfix branch too - hotfix/13.5.2.

/cc. @niftylettuce @andyli9449 @mbalaam - please let's know if all looks good.