Get rid of all the library tags.

lib/src/version_union.dart

 // Copyright (c) 2015, 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.
 
-library pub_semver.src.version_union;
-
 import 'package:collection/collection.dart';
 
 import 'utils.dart';
 import 'version.dart';
 import 'version_constraint.dart';
 import 'version_range.dart';
 
 /// A (package-private) version constraint representing a union of multiple
 /// disjoint version constraints.
 ///
@@ skipping 156 matching lines @@
 
   bool operator ==(other) {
     if (other is! VersionUnion) return false;
     return const ListEquality().equals(constraints, other.constraints);
   }
 
   int get hashCode => const ListEquality().hash(constraints);
 
   String toString() => constraints.join(" or ");
 }