Add version updates to release checklist
So that various other projects can be kept up to date with new releases.
7. Wait for CI release build to finish.
8. Publish release on GitHub from draft made by CI.
9. Update version in `Cargo.toml` to next-dev.
+10. Update clone target version in `getting-started.md` in `website`.
+11. Update downloaded version in `Dockerfile` in `example-echo-server`.
