Update index.html

Fixed a mistake in subject/verb ordering.

"How you can be a web developer without a proficiency in these skills?"

becomes

"How can you be a web developer without a proficiency in these skills?"
Merge pull request #1 from JohnKellyFerguson/patch-2

Update index.html
Update index.html
Merge pull request #3 from eewang/master

Updated index.html
Merge branch 'master' into gh-pages