Fix up example's type signature for Bevy 0.14

examples/custom_asset_lifecycle.rs

@@ -6,10 +6,12 @@
 //! As this example demonstrates, you can bypass the [`ManifestPlugin`](leafwing_manifest::plugin::ManifestPlugin) entirely, and load your assets however you like,
 //! calling the publicly exposed methods yourself to replicate the work it does.
 
+use std::future::Future;
+
 use bevy::{
     asset::{io::Reader, AssetLoader, AsyncReadExt, LoadContext, LoadState},
     prelude::*,
-    utils::BoxedFuture,
+    utils::ConditionalSendFuture,
 };
 use bevy_common_assets::ron::RonLoaderError;
 use leafwing_manifest::manifest::Manifest;
@@ -129,7 +131,9 @@ impl AssetLoader for ItemAssetLoader {
         reader: &'a mut Reader,
         _settings: &'a Self::Settings,
         _load_context: &'a mut LoadContext,
-    ) -> BoxedFuture<'a, Result<Self::Asset, Self::Error>> {
+    ) -> impl ConditionalSendFuture
+           + Future<Output = Result<<Self as AssetLoader>::Asset, <Self as AssetLoader>::Error>>
+    {
         Box::pin(async move {
             let mut bytes = Vec::new();
             reader.read_to_end(&mut bytes).await?;