Bump rust-vmm-ci from f67ef4c to 68d4dbf

Bumps [rust-vmm-ci](https://github.com/rust-vmm/rust-vmm-ci) from `f67ef4c` to `68d4dbf`.
- [Release notes](https://github.com/rust-vmm/rust-vmm-ci/releases)
- [Commits](rust-vmm/rust-vmm-ci@f67ef4c...68d4dbf)

---
updated-dependencies:
- dependency-name: rust-vmm-ci
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]