miner: fix required collateral check

chain/actors/actor_miner.go

@@ -247,7 +247,7 @@ func (sma StorageMinerActor) CommitSector(act *types.Actor, vmctx types.VMContex
 	futurePower := types.BigAdd(self.Power, mi.SectorSize)
 	collateralRequired := CollateralForPower(futurePower)
 
-	if types.BigCmp(collateralRequired, act.Balance) < 0 {
+	if types.BigCmp(act.Balance, collateralRequired) < 0 {
 		return nil, aerrors.New(3, "not enough collateral")
 	}
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/filecoin-project/go-lotus
 
-go 1.12
+go 1.13
 
 require (
 	contrib.go.opencensus.io/exporter/jaeger v0.1.0