disallow_auth option should be in default_url_options and docs

[ageofrage]

disallow_auth option seems to be used in isURL, but it is not in docs, comments nor default_url_options.
https://github.com/validatorjs/validator.js/blob/master/src/lib/isURL.js#L109-L113
https://github.com/validatorjs/validator.js/blob/master/test/validators.test.js#L743-L773

Checklist

• PR contains only changes related; no stray files, etc.
• README updated (where applicable)
• Tests written (where applicable)
• References provided in PR (where applicable)

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (b958bd7) 99.95% compared to head (2c3c036) 99.95%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2293      +/-   ##
==========================================
- Coverage   99.95%   99.95%   -0.01%     
==========================================
  Files         107      107              
  Lines        2454     2449       -5     
  Branches      619      619              
==========================================
- Hits         2453     2448       -5     
  Partials        1        1              

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

... and 3 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.