Bump omz-custom/plugins/zsh-completions from 874917f to 6ff1a67

Bumps [omz-custom/plugins/zsh-completions](https://github.com/zsh-users/zsh-completions) from `874917f` to `6ff1a67`.
- [Release notes](https://github.com/zsh-users/zsh-completions/releases)
- [Commits](zsh-users/zsh-completions@874917f...6ff1a67)

---
updated-dependencies:
- dependency-name: omz-custom/plugins/zsh-completions
  dependency-type: direct:production
...

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