Bump quinn-proto from 0.11.6 to 0.11.8 in /rustbook-en/packages/trpl

Bumps [quinn-proto](https://github.com/quinn-rs/quinn) from 0.11.6 to 0.11.8.
- [Release notes](https://github.com/quinn-rs/quinn/releases)
- [Commits](quinn-rs/quinn@quinn-proto-0.11.6...quinn-proto-0.11.8)

---
updated-dependencies:
- dependency-name: quinn-proto
  dependency-type: indirect
...

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