feat(chain)!: rm local_chain::Update

The intention is to remove the `Update::introduce_older_blocks`
parameter and update the local chain directly with `CheckPoint`.

This simplifies the API and there is a way to do this efficiently.

crates/chain/tests/common/mod.rs

@@ -32,12 +32,9 @@ macro_rules! local_chain {
 macro_rules! chain_update {
     [ $(($height:expr, $hash:expr)), * ] => {{
         #[allow(unused_mut)]
-        bdk_chain::local_chain::Update {
-            tip: bdk_chain::local_chain::LocalChain::from_blocks([$(($height, $hash).into()),*].into_iter().collect())
-                .expect("chain must have genesis block")
-                .tip(),
-            introduce_older_blocks: true,
-        }
+        bdk_chain::local_chain::LocalChain::from_blocks([$(($height, $hash).into()),*].into_iter().collect())
+            .expect("chain must have genesis block")
+            .tip()
     }};
 }
 

crates/chain/tests/test_local_chain.rs

@@ -3,7 +3,7 @@ use std::ops::{Bound, RangeBounds};
 use bdk_chain::{
     local_chain::{
         AlterCheckPointError, ApplyHeaderError, CannotConnectError, ChangeSet, CheckPoint,
-        LocalChain, MissingGenesisError, Update,
+        LocalChain, MissingGenesisError,
     },
     BlockId,
 };
@@ -17,7 +17,7 @@ mod common;
 struct TestLocalChain<'a> {
     name: &'static str,
     chain: LocalChain,
-    update: Update,
+    update: CheckPoint,
     exp: ExpectedResult<'a>,
 }