Fix archiving problem since 1.4.0 (#2641)

* Fix BindingReducer.swift

After discussion with Jon Shier (@jshier) on the Slack, he suggested making this change.
It appears to fix the key path getter error that was appearing when trying to archive a project using the BindingReducer.
I've tested a project which compiled but failed to archive on TCA 1.4 onwards, when macros were introduced, and this change allows it to compile and archive successfully.

* Update Sources/ComposableArchitecture/Reducer/Reducers/BindingReducer.swift

---------

Co-authored-by: Stephen Celis <[email protected]>

Author: rhysm94

Sources/ComposableArchitecture/Reducer/Reducers/BindingReducer.swift

@@ -70,7 +70,9 @@ where State == ViewAction.State {
 
   @inlinable
   public func reduce(into state: inout State, action: Action) -> Effect<Action> {
-    guard let bindingAction = self.toViewAction(action).flatMap(\.binding)
+    // NB: Using a closure and not a `\.binding` key path literal to avoid a bug with archives:
+    //     https://github.com/pointfreeco/swift-composable-architecture/pull/2641
+    guard let bindingAction = self.toViewAction(action).flatMap({ $0.binding })
     else { return .none }
 
     bindingAction.set(&state)