chore: use https git submodule urls

[chancehudson]

Right now adding this repo as a git dependence in a Cargo.toml fails due to authentication errors. This change uses unauthenticated URLs for submodules.

Updating git repository `https://github.com/chancehudson/circom-witnesscalc.git`
    Updating git submodule `[email protected]:iden3/circomlib.git`
error: failed to get `circom-witnesscalc` as a dependency of package `mopro-ffi v0.1.0 (/Users/chance/work/mopro/mopro-ffi)`

Caused by:
  failed to load source for dependency `circom-witnesscalc`

Caused by:
  Unable to update https://github.com/chancehudson/circom-witnesscalc.git?branch=submodule-url

Caused by:
  failed to update submodule `test_deps/circomlib`

Caused by:
  failed to fetch submodule `test_deps/circomlib` from [email protected]:iden3/circomlib.git

Caused by:
  failed to authenticate when downloading repository

  * attempted ssh-agent authentication, but no usernames succeeded: `git`

  if the git CLI succeeds then `net.git-fetch-with-cli` may help here
  https://doc.rust-lang.org/cargo/reference/config.html#netgit-fetch-with-cli

Caused by:
  no authentication methods succeeded

[Autoparallel]

Please this! Yes!

[0xJepsen]

This would be a great help!