[Snyk] Security upgrade html-proofer from 3.7.2 to 3.15.0#44

lyoha1988 wants to merge 1 commit intomasterlyoha1988/github-slideshow:masterfrom

snyk-fix-d9f7d6c9bec92663fadccf2f734e019clyoha1988/github-slideshow:snyk-fix-d9f7d6c9bec92663fadccf2f734e019cCopy head branch name to clipboard