doc(commit_convention): add new category
doc(commit_convention): add new category

Signed-off-by: Leonardo de Moura <7610bae85f2b530654cc716772f1fe653373e892@microsoft.com>

javra/lean,javra/lean,sp3ctum/lean,digama0/lean,soonhokong/travis_test,javra/lean,fpvandoorn/lean2,htzh/lean,fgdorais/lean,fgdorais/lean,javra/lean,eigengrau/lean,soonhokong/travis_test,Kha/lean,Kha/lean,soonhokong/lean,soonhokong/lean,c-cube/lean,johoelzl/lean,sp3ctum/lean,c-cube/lean,soonhokong/lean,fgdorais/lean,levnach/lean,levnach/lean,leanprover-community/lean,leanprover-community/lean,dselsam/lean,levnach/lean,eigengrau/lean,rlewis1988/lean,leanprover-community/lean,fpvandoorn/lean2,soonhokong/travis_test,UlrikBuchholtz/lean,soonhokong/lean-osx,soonhokong/lean,UlrikBuchholtz/lean,codyroux/lean0.1,soonhokong/lean,leanprover-community/lean,soonhokong/lean-windows,levnach/lean,leodemoura/lean,digama0/lean,leanprover/lean,dselsam/lean,johoelzl/lean,digama0/lean,fpvandoorn/lean2,sp3ctum/lean,leanprover/lean,avigad/lean,codyroux/lean0.1,soonhokong/travis_test,fpvandoorn/lean,fpvandoorn/lean2,c-cube/lean,digama0/lean,sp3ctum/lean,Kha/lean,digama0/lean,soonhokong/lean-windows,htzh/lean,UlrikBuchholtz/lean,soonhokong/lean-windows,Kha/lean,rlewis1988/lean,leodemoura/lean,leanprover-community/lean,soonhokong/lean-osx,avigad/lean,fgdorais/lean,avigad/lean,rlewis1988/lean,leanprover/lean,Kha/lean,codyroux/lean0.1,johoelzl/lean,eigengrau/lean,rlewis1988/lean,fpvandoorn/lean,soonhokong/lean-osx,codyroux/lean0.1,soonhokong/lean-osx,leodemoura/lean,soonhokong/lean-windows,htzh/lean,johoelzl/lean,fpvandoorn/lean,sp3ctum/lean,avigad/lean,fpvandoorn/lean,fgdorais/lean,c-cube/lean,rlewis1988/lean,avigad/lean,fgdorais/lean,johoelzl/lean,leanprover/lean,Kha/lean,eigengrau/lean,dselsam/lean,c-cube/lean,dselsam/lean,leodemoura/lean,htzh/lean,leodemoura/lean,avigad/lean,rlewis1988/lean,leanprover/lean,dselsam/lean,digama0/lean,leanprover-community/lean,levnach/lean,soonhokong/lean-osx,fpvandoorn/lean2,UlrikBuchholtz/lean,fpvandoorn/lean,leodemoura/lean,fpvandoorn/lean,leanprover/lean,johoelzl/lean,javra/lean,eigengrau/lean,htzh/lean,UlrikBuchholtz/lean,dselsam/lean,soonhokong/lean-windows