fix 3.0 gemfile
fix 3.0 gemfile

middleman/middleman-sprockets,williamcoates/middleman-sprockets,middleman/middleman-sprockets,ryanmark/middleman-sprockets,williamcoates/middleman-sprockets,middleman/middleman-sprockets,ryanmark/middleman-sprockets,ryanmark/middleman-sprockets,williamcoates/middleman-sprockets