Add dispose to FutureProvider

Author: RossComputerGuy

packages/provider/lib/src/async_provider.dart

@@ -185,6 +185,7 @@ class FutureProvider<T> extends DeferredInheritedProvider<Future<T>?, T> {
     Key? key,
     required Create<Future<T>?> create,
     required T initialData,
+    Dispose<T>? dispose,
     ErrorBuilder<T>? catchError,
     UpdateShouldNotify<T>? updateShouldNotify,
     bool? lazy,
@@ -195,6 +196,7 @@ class FutureProvider<T> extends DeferredInheritedProvider<Future<T>?, T> {
           lazy: lazy,
           builder: builder,
           create: create,
+          dispose: dispose,
           updateShouldNotify: updateShouldNotify,
           startListening: _futureStartListening(
             catchError: catchError,