Bump submodules/vipr from 591ed4f to 2c9ed0a

Bumps [submodules/vipr](https://github.com/microsoft/vipr) from `591ed4f` to `2c9ed0a`.
- [Release notes](https://github.com/microsoft/vipr/releases)
- [Commits](microsoft/Vipr@591ed4f...2c9ed0a)

---
updated-dependencies:
- dependency-name: submodules/vipr
  dependency-type: direct:production
...

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

Author: dependabot[bot]