Remove FilterRelation.In / "property IN" queries, upgrade googleapis{,_beta} dependencies

lib/datastore.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// This library provides a low-level API for accessing Google's Cloud
 /// Datastore.
 ///
 /// For more information on Cloud Datastore, please refer to the following
 /// developers page: https://cloud.google.com/datastore/docs
 library gcloud.datastore;
@@ skipping 222 matching lines @@
 }
 
 /// A relation used in query filters.
 class FilterRelation {
   static const FilterRelation LessThan = const FilterRelation._('<');
   static const FilterRelation LessThanOrEqual = const FilterRelation._('<=');
   static const FilterRelation GreatherThan = const FilterRelation._('>');
   static const FilterRelation GreatherThanOrEqual =
       const FilterRelation._('>=');
   static const FilterRelation Equal = const FilterRelation._('==');
-  static const FilterRelation In = const FilterRelation._('IN');
 
   final String name;
 
   const FilterRelation._(this.name);
 
   String toString() => name;
 }
 
 /// A filter used in queries.
 class Filter {
@@ skipping 158 matching lines @@
   /// If a [transaction] is given, the query will be within this transaction.
   /// But note that arbitrary queries within a transaction are not possible.
   /// A transaction is limited to a very small number of entity groups. Usually
   /// queries with transactions are restricted by providing an ancestor filter.
   ///
   /// Outside of transactions, the result set might be stale. Queries are by
   /// default eventually consistent.
   Future<Page<Entity>> query(
       Query query, {Partition partition, Transaction transaction});
 }