Remove // from mev-rs patch section

[michaelsproul]

Issue Addressed

A user on Discord reported being unable to compile from source due to errors caused by the // in some of our Git dependency URLs.

$ make
cargo install --path lighthouse --force --locked \
        --features "jemalloc" \
        --profile "release" \

  Installing lighthouse v4.2.0 (/samsung_8tb_ssd/lighthouse/lighthouse)
    Updating git repository `https://github.com/ralexstokes//ethereum-consensus`
warning: spurious network error (3 tries remaining): remote error: 
 ralexstokes//ethereum-consensus is not a valid repository name
Visit https://support.github.com/ for help; class=Net (12)
warning: spurious network error (2 tries remaining): remote error: 
 ralexstokes//ethereum-consensus is not a valid repository name
Visit https://support.github.com/ for help; class=Net (12)
warning: spurious network error (1 tries remaining): remote error: 
 ralexstokes//ethereum-consensus is not a valid repository name
Visit https://support.github.com/ for help; class=Net (12)
error: failed to load source for dependency `ethereum-consensus`

I haven't been able to reproduce the error on my machine, but this may be due to hitting a different github.com server or some caching I'm unaware of (I tried deleting ~/.cargo/git/checkouts/<package> without success).

Proposed Changes

Use www.github.com to patch the deps instead of //. I'm not sure if we can remove the [patch] entirely until mev-rs does. I get weird circular errors about the package name being either ssz-rs or ssz_rs when I try to just pin the commits in the Cargo.toml.

Additional Info

• mev-rs issue: Fails to Build Due to Cargo Patch ralexstokes/mev-rs#91
• Cargo issue: Patching dependencies does not work if it's for the same location but a different branch rust-lang/cargo#5478

[michaelsproul]

Alex has published new upstream versions, so we can remove the patches entirely. I'll update this PR shortly.

[michaelsproul]

Closing this in favour of a new PR.