Disallow withdrawn EIPs in the requires header

[khawlahssn]

Resolves #62

[SamWilsn]

I think all that's left on this one is updating a few tests in eipw-lint-js. For example:

https://github.com/ethereum/eipw/blob/97e667a6ec71aded1e26121058f310351cee0a3f/eipw-lint-js/tests/main.rs#L400

Thanks so much for your help!