Migrate everything to the 2018 edition (#1758)

substrate/core/consensus/aura/slots/Cargo.toml

@@ -6,7 +6,7 @@ description = "Generic slots-based utilities for consensus"
 edition = "2018"
 
 [dependencies]
-parity-codec = "3.0"
+codec = { package = "parity-codec", version = "3.0" }
 client = { package = "substrate-client", path = "../../../client" }
 primitives = { package = "substrate-primitives", path = "../../../primitives" }
 runtime_primitives = { package = "sr-primitives", path = "../../../sr-primitives" }

substrate/core/consensus/aura/slots/src/lib.rs

@@ -14,8 +14,6 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-extern crate parity_codec as codec;
-
 mod slots;
 
 pub use slots::{Slots, SlotInfo};
@@ -220,7 +218,7 @@ impl SlotDuration {
 		C: ProvideRuntimeApi,
 		C::Api: AuraApi<B>,
 	{
-		use parity_codec::Decode;
+		use codec::Decode;
 		const SLOT_KEY: &[u8] = b"aura_slot_duration";
 
 		match client.get_aux(SLOT_KEY)? {