Bump ark-r1cs-std from 0.3.1 to 0.4.0 (#1005)

Bumps [ark-r1cs-std](https://github.com/arkworks-rs/r1cs-std) from 0.3.1 to 0.4.0.
- [Release notes](https://github.com/arkworks-rs/r1cs-std/releases)
- [Changelog](https://github.com/arkworks-rs/r1cs-std/blob/master/CHANGELOG.md)
- [Commits](arkworks-rs/r1cs-std@v0.3.1...v0.4.0)

---
updated-dependencies:
- dependency-name: ark-r1cs-std
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Michal Swietek <[email protected]>