chore(core): derive default for log (#1168)

ethers-core/src/types/log.rs

@@ -9,7 +9,7 @@ use serde::{
 use std::ops::{Range, RangeFrom, RangeTo};
 
 /// A log produced by a transaction.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
 pub struct Log {
     /// H160. the contract that emitted the log
     pub address: Address,