Bump h2 in /packages/backend in the cargo group across 1 directory

Bumps the cargo group with 1 update in the /packages/backend directory: [h2](https://github.com/hyperium/h2).


Updates `h2` from 0.3.24 to 0.3.26
- [Release notes](https://github.com/hyperium/h2/releases)
- [Changelog](https://github.com/hyperium/h2/blob/v0.3.26/CHANGELOG.md)
- [Commits](hyperium/h2@v0.3.24...v0.3.26)

---
updated-dependencies:
- dependency-name: h2
  dependency-type: indirect
  dependency-group: cargo
...

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