Define the [`Sealing`](https://github.com/paritytech/frontier/blob/bd5bd374fd50eb30eb381148243c46d882e057d5/template/node/src/cli.rs#L3-L11) enum so the parachain can be configured to use manual-seal as well as instant-seal.
Define the
Sealingenum so the parachain can be configured to use manual-seal as well as instant-seal.