Bump hex from 0.4.2 to 0.4.3 in /rust

[dependabot[bot]]

Bumps hex from 0.4.2 to 0.4.3.

Commits

• b2b4370 Release v0.4.3
• 11fb8b5 README: Remove Travis badge
• e188c3d Update dev-dependencies.
• 7fe0e5a Fix formatting and some build warnings.
• bfe146e ci (gitlab-ci): Use gitlab-ci matrix feature.
• a354af2 Add alloc feature (#42)
• d8fa31f Fix typos in ToHex Doc comments
• See full diff in compare view

You can trigger a rebase of this PR by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot close will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually