Bump html-proofer from 3.17.2 to 3.17.4

Bumps html-proofer from 3.17.2 to 3.17.4.

Commits

• e09f6be 💎 bump to 3.17.4
• a830821 Merge pull request #605 from gjtorikian/cache-crash
• ef4eafa Correct internal links when pulled from outdated cache
• 21b0edd 💎 bump to 3.17.3
• 0f0722a Merge pull request #603 from gjtorikian/broken-hash-reporting
• d4c5b30 lint
• 93d4235 Provide path to issue creation
• ebd9d4c no need
• b2af233 Merge pull request #600 from gjtorikian/add-ci-linting
• ea5eea2 bust cache I guess
• Additional commits viewable in compare view