Refactored `nothing_to_commit?` to `uncommitted_changes?`
Refactored `nothing_to_commit?` to `uncommitted_changes?`

Helping to avoid a double negative in the logic

edgecase/middleman-gh-pages,neo/middleman-gh-pages,patilswapnilv/middleman-gh-pages,rmm5t/middleman-gh-pages