Update AppVeyor config.
Update AppVeyor config.

Install gems in ./vendor/bundle and cache those only.

noikiy/jekyll,jekyll/jekyll,yhironaka/yhironaka.github.io,tillgrallert/jekyll,darwin/jekyll,Strangehill/jekyll,gencer/jekyll,jekyll/jekyll,gencer/jekyll,fulldecent/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,rlugojr/jekyll,ZDroid/jekyll,tillgrallert/jekyll,getandpost/jekyll.github.io,tomjohnson1492/jekyll,alex-kovac/jekyll,tomjohnson1492/jekyll,alfredxing/jekyll,ryanshaw/jekyll,jekyll/jekyll,alfredxing/jekyll,fulldecent/jekyll,tomjohnson1492/jekyll,chrisfinazzo/jekyll,ZDroid/jekyll,xiebinhqy/jklly_china,rasa2011/rasa2011.github.io,chrisfinazzo/jekyll,xiebinhqy/jklly_china,alfredxing/jekyll,noikiy/jekyll,rlugojr/jekyll,ryanshaw/jekyll,x-way/jekyll,xiebinhqy/jklly_china,darwin/jekyll,Strangehill/jekyll,noikiy/jekyll,alfredxing/jekyll,getandpost/jekyll.github.io,Strangehill/jekyll,jaybe-jekyll/jekyll,gencer/jekyll,ryanshaw/jekyll,rasa2011/rasa2011.github.io,alex-kovac/jekyll,Strangehill/jekyll,Strangehill/jekyll,gencer/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,jaybe-jekyll/jekyll,alex-kovac/jekyll,alex-kovac/jekyll,tillgrallert/jekyll,x-way/jekyll,jaybe-jekyll/jekyll,xiebinhqy/jklly_china,tillgrallert/jekyll,alex-kovac/jekyll,darwin/jekyll,tomjohnson1492/jekyll,tomjohnson1492/jekyll,noikiy/jekyll,x-way/jekyll,darwin/jekyll,gencer/jekyll,x-way/jekyll,tillgrallert/jekyll,rlugojr/jekyll,rasa2011/rasa2011.github.io,jaybe-jekyll/jekyll,getandpost/jekyll.github.io,ryanshaw/jekyll,ZDroid/jekyll,jekyll/jekyll,rlugojr/jekyll