Use pub_semver package in pub.

sdk/lib/_internal/pub_generated/lib/src/command/cache_add.dart

Index: sdk/lib/_internal/pub_generated/lib/src/command/cache_add.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/command/cache_add.dart b/sdk/lib/_internal/pub_generated/lib/src/command/cache_add.dart
index 8e9d45bd1c19055cc62215da452f91398c0997dd..2b40239b10c0a583167a5b9c6c0d91c27ee745e8 100644
--- a/sdk/lib/_internal/pub_generated/lib/src/command/cache_add.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/command/cache_add.dart
@@ -1,10 +1,10 @@
 library pub.command.cache_add;
 import 'dart:async';
+import 'package:pub_semver/pub_semver.dart';
 import '../command.dart';
 import '../log.dart' as log;
 import '../package.dart';
 import '../utils.dart';
-import '../version.dart';
 class CacheAddCommand extends PubCommand {
   String get description => "Install a package.";
   String get usage =>