op-node: Fix block numbe rin rollup config generation (#3399)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

op-node/cmd/genesis/cmd.go

@@ -182,7 +182,7 @@ func makeRollupConfig(
 		Genesis: rollup.Genesis{
 			L1: eth.BlockID{
 				Hash:   l1StartBlock.Hash(),
-				Number: 0,
+				Number: l1StartBlock.NumberU64(),
 			},
 			L2: eth.BlockID{
 				Hash:   l2Genesis.ToBlock().Hash(),