Bump html-proofer from 3.15.3 to 3.16.0

Bumps html-proofer from 3.15.3 to 3.16.0.

Release notes

Sourced from html-proofer's releases.

v3.16.0

• Add support for before_request: https://github.com/gjtorikian/html-proofer/pull/577

Commits

• 0c57c0f 💎 bump to 3.16.0
• b85158a 💎 bump to 3.16.0
• a9be443 Merge pull request #577 from asbjornu/feature/before-request
• 96e7e42 Update README
• c78946b Merge pull request #578 from gjtorikian/allow-at-sign
• 2ef0ae5 Rubocop
• 73a747f Correctly broken
• 463781a Allow for at-signs
• 7e814fc Add HTMLProofer::Runner#before_request
• See full diff in compare view