submodules: bump external/cli from 8a1f197 to 7ef1976

Bumps [external/cli](https://github.com/oasisprotocol/cli) from `8a1f197` to `7ef1976`.
- [Release notes](https://github.com/oasisprotocol/cli/releases)
- [Commits](oasisprotocol/cli@8a1f197...7ef1976)

---
updated-dependencies:
- dependency-name: external/cli
  dependency-type: direct:production
...

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