update pub to get --build-delay arg and remove require.js loading timeouts

CHANGELOG.md

 ## 1.25.0
 
 ### Language
 * A string in a `part of` declaration may now be used to refer to the library
   this file is part of.
   A library part can now declare its library either as:
   `part of name.of.library;` or as `part of "uriReferenceOfLibrary.dart";`.
   This allows libraries with no library declarations (and therefore no name)
   to have parts, and it allows tools to easily find the library of a part
   file.
@@ skipping 30 matching lines @@
     dependencies:
       foobar:
         git:
           url: git://github.com/dart-lang/multi_package_repo
           path: pkg/foobar
     ```
 
   * `pub get` and `pub upgrade` properly produce an error message and exit code
     when no network is present.
 
-  * Bug fixes for dartdevc support in `pub serve`.
+  * `pub serve` now waits for file watcher events to stabilize before scheduling
+     new builds. This helps specifically with `safe-write` features in editors,
+     as well as other situations such as `save all` which cause many fast edits.
 
-    * Fixed module config invalidation logic so modules are properly
-      recalculated when package layout changes.
-    * Fixed exception when handling require.js errors that aren't script load
-      errors.
-    * Fixed an issue where requesting the bootstrap.js file before the dart.js
-      file would result in a 404.
-    * Fixed a Safari issue during bootstrapping (note that Safari is still not
-      officially supported but does work for trivial examples).
+  * Added the `--build-delay` argument to `pub serve` which sets the amount of
+    time (in ms) to wait between file watcher events before scheduling a build.
+    Defaults to 50.
+
+  * Removed require.js module loading timeout for dartdevc, which resolves an
+    issue where the initial load of an app might give a timeout error.
 
 ## 1.24.2 - 22-06-2017
 
 * Fixes for debugging in Dartium.
   * Fix DevConsole crash with JS
       (https://github.com/dart-lang/sdk/issues/29873).
   * Fix debugging in WebStorm, NULL returned for JS objects
       (https://github.com/dart-lang/sdk/issues/29854).
 
 ## 1.24.1 - 14-06-2017
@@ skipping 2081 matching lines @@
     they will keep the Dart process alive until they time out. This fixes the
     handling of persistent connections. Previously, the client would shut down
     immediately after a request.
 
   * **Breaking change:** `HttpServer` no longer compresses all traffic by
     default. The new `autoCompress` property can be set to `true` to re-enable
     compression.
 
 * `dart:isolate`: `Isolate.spawnUri` added the optional `packageRoot` argument,
   which controls how it resolves `package:` URIs.