l2geth: fix bad flag parsing

The parsing of the `ROLLUP_FEE_THRESHOLD_UP` and
`ROLLUP_FEE_THRESHOLD_DOWN` config options were set to be boolean flags
instead of float64 flags. The config flags wouldn't parse if a float64
was used as a bool flag.

.changeset/six-cobras-fold.md

+---
+'@eth-optimism/l2geth': patch
+---
+
+Fixes the flags to use float64 instead of bools for the `--rollup.feethresholddown` and `-rollup.feethresholdup` config options

l2geth/cmd/utils/flags.go

@@ -898,12 +898,12 @@ var (
 		Usage:  "Disable transactions with 0 gas price",
 		EnvVar: "ROLLUP_ENFORCE_FEES",
 	}
-	RollupFeeThresholdDownFlag = cli.BoolFlag{
+	RollupFeeThresholdDownFlag = cli.Float64Flag{
 		Name:   "rollup.feethresholddown",
 		Usage:  "Allow txs with fees below the current fee up to this amount, must be < 1",
 		EnvVar: "ROLLUP_FEE_THRESHOLD_DOWN",
 	}
-	RollupFeeThresholdUpFlag = cli.BoolFlag{
+	RollupFeeThresholdUpFlag = cli.Float64Flag{
 		Name:   "rollup.feethresholdup",
 		Usage:  "Allow txs with fees above the current fee up to this amount, must be > 1",
 		EnvVar: "ROLLUP_FEE_THRESHOLD_UP",