feat(frontends/lean/dependencies): do not stop computing dependencies at error, compute as many as possible, and sign error in the end
feat(frontends/lean/dependencies): do not stop computing dependencies at error, compute as many as possible, and sign error in the end

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

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