fix: fix the gas price check for opBNB #210

Job	Run time
docs / optimism	1m 34s
clippy / optimism	1m 42s
docs / bsc	1m 36s
check	59s
clippy / bsc	1m 48s
fmt	14s
check serde	59s
check std	56s
test stable --no-default-features	2m 53s
TyposCheck	5s
test stable	2m 48s
test stable --features bsc	3m 4s
test stable --features optimism,opbnb	3m 15s
test beta --no-default-features	3m 4s
test beta	2m 59s
test beta --features bsc	3m 11s
test beta --features optimism,opbnb	3m 14s
test nightly --no-default-features	2m 45s
test nightly	2m 40s
test nightly --features bsc	2m 43s
test nightly --features optimism,opbnb	3m 1s
	45m 30s

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