types: Re-export cid's multihash to construct CID V1

[bkontur]

For example in polkadot-sdk

-	use litep2p::types::multihash::Code;
+	use litep2p::types::{cid::{Cid as LiteP2pCid, multihash::Multihash as LiteP2pMultihash}, multihash::Code as LiteP2pMultihashCode};
 

-							block: cid::Cid::new_v1(
+							block: LiteP2pCid::new_v1(
 								0x70,
-								cid::multihash::Multihash::wrap(
-									u64::from(Code::Blake2b256),
+								LiteP2pMultihash::wrap(
+									u64::from(LiteP2pMultihashCode::Blake2b256),
 									&[0u8; 32],
 								)

[lexnv]

nit: since these PRs will eventually end up in the changelog, we could be a bit more specific with naming (ie, something like: types: Re-export multihash to construct CID V1)

[dmitry-markin]

We should eventually bump multihash in litep2p to the common version with cid.

[bkontur]

We should eventually bump multihash in litep2p to the common version with cid.

that's what I exactly tried, but didn't push here, because there is more to bump with it :)

Let's do as a separate PR