fetch: add user-agent
fetch: add user-agent

Fix: #1247

cab105/rkt,luebken/rkt,dalanlan/rkt,liubq919/rkt,alban/rkt,intfrr/rkt,squeed/rkt,dalanlan/rkt,achanda/rkt,iankronquist/rkt,intelsdi-x/rkt,Wilybald/rkt,tmrts/rkt,mike1729/rkt,coreos/rkt,intfrr/rkt,shobhit85/rkt,luebken/rkt,joshix/rkt,blixtra/rkt,endocode/rkt,chrisseto/rkt,tmrts/rkt,coreos/rkt,kinvolk/rkt,tv42/rkt,joshix/rkt,intfrr/rkt,ybubnov/rkt,jasonchaffee/rkt,rkt/rkt,shobhit85/rkt,akshaykarle/rkt,akshaykarle/rkt,markllama/rkt,monstermunchkin/rkt,sgotti/rkt,achanda/rkt,jakon89/rkt,sinfomicien/rkt,jakon89/rkt,ybubnov/rkt,jasonchaffee/rkt,luebken/rkt,MattDees/rkt,jonboulle/rkt,linki/rkt,alexhersh/rkt,sinfomicien/rkt,Shashwatsh/rkt,liugenping/rkt,yifan-gu/rkt,iaguis/rkt,mike1729/rkt,jakon89/rkt,intelsdi-x/rkt,matthaias/rkt,shobhit85/rkt,adfernandes/rkt,lucasallan/rkt,monstermunchkin/rkt,kbrwn/rkt,cab105/rkt,sinfomicien/rkt,kinvolk/rkt,nhlfr/rkt,euank/rkt,krnowak/rkt,akshaykarle/rkt,dalanlan/rkt,lee212/rkt,alban/rkt,dgonyeo/rkt,linki/rkt,Yhgenomics/rkt,MattDees/rkt,yifan-gu/rkt,nhlfr/rkt,dgonyeo/rkt,Shashwatsh/rkt,kinvolk/rkt,nhlfr/rkt,Wilybald/rkt,s-urbaniak/rkt,Wilybald/rkt,monstermunchkin/rkt,liugenping/rkt,jonboulle/rkt,mjg59/rkt,adfernandes/rkt,liubq919/rkt,mjg59/rkt,iankronquist/rkt,yifan-gu/rocket,rkt/rkt,joshix/rkt,yifan-gu/rocket,kbrwn/rkt,achanda/rkt,intelsdi-x/rkt,squeed/rkt,smarvin/rkt,jjlakis/rkt,lucasallan/rkt,marineam/rkt,s-urbaniak/rkt,marineam/rkt,squeed/rkt,kbrwn/rkt,euank/rkt,markllama/rkt,Wilybald/rkt,jjlakis/rkt,il9ue/rkt,ybubnov/rkt,matthaias/rkt,cab105/rkt,blixtra/rkt,sstabellini/rkt,endocode/rkt,krnowak/rkt,rkt/rkt,euank/rkt,jzelinskie/rkt,yifan-gu/rocket,sstabellini/rkt,s-urbaniak/rkt,joshix/rkt,yifan-gu/rkt,liugenping/rkt,markllama/rkt,chrisseto/rkt,sgotti/rkt,tv42/rkt,matthaias/rkt,Yhgenomics/rkt,alban/rkt,dgonyeo/rkt,linki/rkt,iaguis/rkt,jonboulle/rkt,liubq919/rkt,mjg59/rkt,jzelinskie/rkt,blixtra/rkt,MattDees/rkt,rkt/rkt,sstabellini/rkt,jasonchaffee/rkt,iankronquist/rkt,adfernandes/rkt,jzelinskie/rkt,il9ue/rkt,lee212/rkt,lucasallan/rkt,mike1729/rkt,tv42/rkt,Yhgenomics/rkt,iaguis/rkt,jjlakis/rkt,krnowak/rkt,kinvolk/rkt,alexhersh/rkt,tmrts/rkt,lucasallan/rkt,lee212/rkt,coreos/rkt,smarvin/rkt,alexhersh/rkt,il9ue/rkt,smarvin/rkt,chrisseto/rkt,marineam/rkt,Shashwatsh/rkt,sgotti/rkt,endocode/rkt