Makefile: Do not fail build on missing lessc
Makefile: Do not fail build on missing lessc

This is achieved by adding public/css/gogs.css to special .IGNORE target, which
makes inability to generate/update gogs.css non-fatal and not stopping whole
build process. User is still notified about missing lessc command though, since
inability to update CSS may lead to potential problems:

    lessc public/less/gogs.less public/css/gogs.css
    make: lessc: No such file or directory
    make: [public/css/gogs.css] Error 1 (ignored)

More info at:

  https://www.gnu.org/software/make/manual/html_node/Special-Targets.html

svcavallar/gogs,chriswatt/gogs,pikacloud/pikacode,spacetourist/gitea,dancewing/gogs,kubatyszko/gitea,gigforks/gogs,ethantkoenig/gogs,denji/gitea_tmp,dlob/gogs,cybe/gitea,bkcsoft/gogs,kjellkvinge/gitea,svcavallar/gogs,sapk/gogs,rems4e/gitea,cem/gogs,geek1011/gitea,cgars/gogs,andreynering/gitea,avelino/gitea,jvanderneutstulen/gogs,cumgun/gitea,bygreencn/gogs,everhopingandwaiting/gogs,xaionaro/gogs,cgars/gogs,pentix/gogs,liliexuan/gogs,dlob/gogs,gigforks/gogs,Bwko/gitea,odinuge/gogs,typeless/gitea,go-gitea/gitea,kjellkvinge/gitea,mark77z/tt2016,Spice-King/gogs,tanapoln/gogs,gigforks/gogs,jvanderneutstulen/gogs,willemvd/gitea,pentix/gogs,sillydong/gogs,ForxaCoLab/forxa,lafriks/gitea,mukaiu/gogs,strk/gogs,manfer/gogs,gogits/gogs,vCaesar/gitea,typeless/gitea,typeless/gitea,Bwko/gitea,ethantkoenig/gitea,tony/gogs,ethantkoenig/gogs,sapk/gogs,tszym/gogs,tszym/gogs,linquize/gogs,mark77z/tt2016,dl5rcw/gitea,vCaesar/gitea,lunny/gitea,psolyca/gitea,spacetourist/gitea,tanapoln/gogs,AndreaGiardini/gogs,gogits/gogs,sapk/gogs,avelino/gitea,likeit92/gogs,likeit92/gogs,psaavedra/gogs,bkcsoft/gogs,gigforks/gogs,dlob/gogs,dancewing/gogs,bkcsoft/gogs,dnmgns/gitea,go-gitea/gitea,kong36088/SCAUGogits,cem/gogs,odinuge/gogs,jorgesumle/gitea,rems4e/gitea,xormplus/gitea,kjellkvinge/gitea,CaeruleusAqua/gitea,tony/gogs,kong36088/SCAUGogits,0rax/gogs,mark77z/tt2016,lunny/gitea,wangjild/gogs,chriswatt/gogs,strk/gogs,dancewing/gogs,Spice-King/gogs,JonasFranzDEV/gitea,avelino/gitea,everhopingandwaiting/gogs,dancewing/gogs,cez81/gitea,lafriks/gitea,dnmgns/gitea,CaeruleusAqua/gitea,cybe/gitea,cgars/gogs,geek1011/gitea,0rax/gogs,tboerger/gitea,gogits/gogs,psolyca/gitea,AndreaGiardini/gogs,liliexuan/gogs,xaionaro/gogs,sillydong/gogs,DblK/gitea,pentix/gogs,kong36088/SCAUGogits,JonasFranzDEV/gitea,typeless/gitea,bygreencn/gogs,jvanderneutstulen/gogs,makhov/gitea,sapk-fork/gitea,andreynering/gitea,minecrafter/gitea,sapk-fork/gitea,DblK/gitea,denji/gitea,linquize/gogs,mjwwit/gitea,lafriks/gitea,richmahn/gogs,Morlinest/gitea,admik/gitea,0rax/gogs,ethantkoenig/gitea,mukaiu/gogs,chriswatt/gogs,denji/gitea_tmp,Spice-King/gogs,tszym/gogs,wangjild/gogs,odinuge/gogs,cem/gogs,kubatyszko/gitea,mukaiu/gogs,psaavedra/gogs,cez81/gitea,cez81/gitea,wangjild/gogs,vdbt/gitea,xaionaro/gogs,cumgun/gitea,sapk-fork/gitea,0rax/gogs,tanapoln/gogs,likeit92/gogs,sillydong/gogs,bygreencn/gogs,everhopingandwaiting/gogs,mjwwit/gitea,vdbt/gitea,tboerger/gitea,dnmgns/gitea,svcavallar/gogs,pikacloud/pikacode,mpindado/gogs,go-gitea/gitea,mpindado/gogs,lunny/gitea,tony/gogs,Bwko/gitea,mpindado/gogs,ForxaCoLab/forxa,tboerger/gitea,ForxaCoLab/forxa,manfer/gogs,pikacloud/pikacode,jorgesumle/gitea,liliexuan/gogs,Morlinest/gitea,avelino/gitea,manfer/gogs,linquize/gogs,kubatyszko/gitea,strk/gogs,everhopingandwaiting/gogs,puffybsd/gitea,AndreaGiardini/gogs,psaavedra/gogs,denji/gitea_tmp,sapk-fork/gitea,richmahn/gogs,denji/gitea_tmp