Update internal generated files

lib/src/descriptor.pb.dart

 ///
 //  Generated code. Do not modify.
 ///
-library Descriptor.pb;
+library proto2;
 
 import 'dart:typed_data';
 
+import 'package:fixnum/fixnum.dart';
 import 'package:protobuf/protobuf.dart';
 
 class FileDescriptorSet extends GeneratedMessage {
   static final BuilderInfo _i = new BuilderInfo('FileDescriptorSet')
     ..m(1, 'file', () => new FileDescriptorProto(), () => new PbList<FileDescriptorProto>())
   ;
 
   FileDescriptorSet() : super();
   FileDescriptorSet.fromBuffer(List<int> i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromBuffer(i, r);
   FileDescriptorSet.fromJson(String i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromJson(i, r);
@@ skipping 684 matching lines @@
   UninterpretedOption clone() => new UninterpretedOption()..mergeFromMessage(this);
   BuilderInfo get info_ => _i;
 
   List<UninterpretedOption_NamePart> get name => getField(2);
 
   String get identifierValue => getField(3);
   void set identifierValue(String v) { setField(3, v); }
   bool hasIdentifierValue() => hasField(3);
   void clearIdentifierValue() => clearField(3);
 
-  ByteData get positiveIntValue => getField(4);
-  void set positiveIntValue(ByteData v) { setField(4, v); }
+  Int64 get positiveIntValue => getField(4);
+  void set positiveIntValue(Int64 v) { setField(4, v); }
   bool hasPositiveIntValue() => hasField(4);
   void clearPositiveIntValue() => clearField(4);
 
-  ByteData get negativeIntValue => getField(5);
-  void set negativeIntValue(ByteData v) { setField(5, v); }
+  Int64 get negativeIntValue => getField(5);
+  void set negativeIntValue(Int64 v) { setField(5, v); }
   bool hasNegativeIntValue() => hasField(5);
   void clearNegativeIntValue() => clearField(5);
 
   double get doubleValue => getField(6);
   void set doubleValue(double v) { setField(6, v); }
   bool hasDoubleValue() => hasField(6);
   void clearDoubleValue() => clearField(6);
 
   List<int> get stringValue => getField(7);
   void set stringValue(List<int> v) { setField(7, v); }
@@ skipping 32 matching lines @@
 
   SourceCodeInfo() : super();
   SourceCodeInfo.fromBuffer(List<int> i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromBuffer(i, r);
   SourceCodeInfo.fromJson(String i, [ExtensionRegistry r = ExtensionRegistry.EMPTY]) : super.fromJson(i, r);
   SourceCodeInfo clone() => new SourceCodeInfo()..mergeFromMessage(this);
   BuilderInfo get info_ => _i;
 
   List<SourceCodeInfo_Location> get location => getField(1);
 }