docs: fix README logo inline styles for GitHub
docs: fix README logo inline styles for GitHub

GitHub remove all inline styles but `max-width: 100%`

colin-marshall/foundation-sites,denisahac/foundation-sites,zurb/foundation,zurb/foundation-sites,zurb/foundation-sites,colin-marshall/foundation-sites,colin-marshall/foundation-sites,denisahac/foundation-sites,zurb/foundation,DaSchTour/foundation-sites,DaSchTour/foundation-sites,zurb/foundation,denisahac/foundation-sites,abdullahsalem/foundation-sites,abdullahsalem/foundation-sites,zurb/foundation-sites,atmmarketing/foundation-sites,atmmarketing/foundation-sites,abdullahsalem/foundation-sites,atmmarketing/foundation-sites