update pub to get latest dartdevc fixes

CHANGELOG.md

 ## 1.25.0
 
 ### Language
 
 #### Strong Mode
 
 ### Core library changes
 
 * `dart:io`
   * Unified backends for `SecureSocket`, `SecurityContext`, and
     `X509Certificate` to be consistent across all platforms. All
     `SecureSocket`, `SecurityContext`, and `X509Certificate` properties and
     methods are now supported on iOS and OSX.
   * Deprecated `SecurityContext.alpnSupported` as ALPN is now supported on all
     platforms.
 
 ### Dart VM
 
 ### Tool Changes
 
 * Pub
 
   * `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`.
+    * 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).
 
 ## 1.24.0
 
 ### Language
 * During a dynamic type check, `void` is not required to be `null` anymore.
   In practice, this makes overriding `void` functions with non-`void` functions
   safer.
 
 * During static analysis, a function or setter declared using `=>` with return
   type `void` now allows the returned expression to have any type. For example,
@@ skipping 119 matching lines @@
 ### Tool Changes
 
 * Dartium
 
   Dartium is now based on Chrome v50. See *Core library changes* above for
   details on the changed APIs.
 
 * Pub
 
   * `pub build` and `pub serve`
-  
+
     * Added support for the Dart Development Compiler.
 
       Unlike dart2js, this new compiler is modular, which allows pub to do
       incremental re-builds for `pub serve`, and potentially `pub build` in the
       future.
 
       In practice what that means is you can edit your Dart files, refresh in
       Chrome (or other supported browsers), and see your edits almost
       immediately. This is because pub is only recompiling your package, not all
       packages that you depend on.
@@ skipping 25 matching lines @@
       `pub serve test --web-compiler=dartdevc`, and then run
       `pub run test -p chrome --pub-serve=8080`.
 
     * The `--no-dart2js` flag has been deprecated in favor of
       `--web-compiler=none`.
 
     * `pub build` will use a failing exit code if there are errors in any
       transformer.
 
   * `pub publish`
-  
+
     * Added support for the UNLICENSE file.
 
     * Packages that depend on the Flutter SDK may be published.
 
   * `pub get` and `pub upgrade`
 
     * Don't dump a stack trace when a network error occurs while fetching
       packages.
 
 * dartfmt
@@ skipping 1858 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.