Update zlint to get close-primes lint, remove our own

[aarongable]

zlint now has a close-primes checker: zmap/zlint#674

we should update our dependency on zlint to a version that contains this new lint, and then consider removing our own one-off check:

boulder/goodkey/good_key.go

Line 388 in 89000bd

func checkPrimeFactorsTooClose(n *big.Int, rounds int) error {

[andygabby]

There are a few TLDs that have been removed by ICANN, so +1 to updating zlint.

[aarongable]

Turns out I already updated us to v3.4.0 which contains these updated checks, and just forgot to tie it to this bug: #6462