fix: Parachain example tokio version (#1317)

* Update cargo.lock

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* parachain: Bump tokio dependency

The tokio dependency is bumped to version 1.34. Ideally, we would use
the workspace feature to pull in the tokio version. However, the
parachain example is not part of the workspace, because it depends on
non mutually exclusive feature flags.

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* parachain: Bump tokio dependency to 1.35

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

---------

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>