Change Eth1Data.block_hash type to Hash32

specs/merge/beacon-chain.md

@@ -16,6 +16,8 @@
   - [Transition](#transition)
   - [Execution](#execution)
 - [Containers](#containers)
+  - [Updated containers](#updated-containers)
+    - [`Eth1Data`](#eth1data)
   - [Extended containers](#extended-containers)
     - [`BeaconBlockBody`](#beaconblockbody)
     - [`BeaconState`](#beaconstate)
@@ -67,6 +69,19 @@ We define the following Python custom types for type hinting and readability:
 
 ## Containers
 
+### Modified containers
+
+#### `Eth1Data`
+
+*Note*: The only modification is the type of `block_hash` field that is changed to `Hash32`.
+
+```python
+class Eth1Data(Container):
+    deposit_root: Root
+    deposit_count: uint64
+    block_hash: Hash32  # [Modified in Merge]
+```
+
 ### Extended containers
 
 *Note*: Extended SSZ containers inherit all fields from the parent in the original