Bring in the latest Pub.

CHANGELOG.md

 ## 1.13.0
 
 * `dart:core`
   * `Uri` added `removeFragment` method.
   * `String.allMatches` (implementing `Pattern.allMatches`) is now lazy,
     as all `allMatches` implementations are intended to be.
 * `dart:io`
   * `HttpClient` no longer sends URI fragments in the requeust. This is not
     allowed by the HTTP protocol.
     The `HttpServer` still gracefully receives fragments, but discards them
@@ skipping 34 matching lines @@
   * Change stdout/stderr to binary mode on Windows.
     [4205b29](https://github.com/dart-lang/sdk/commit/4205b2997e01f2cea8e2f44c6f46ed6259ab7277)
 
 * `dart:mirrors`
   * `InstanceMirror.delegate` moved up to `ObjectMirror`.
 
 ### Tool changes
 
 * Pub
 
+  * **Breaking:** various commands that previously ran `pub get` implicitly no
+    longer do so. Instead, they merely check to make sure the ".packages" file
+    is newer than the pubspec and the lock file, and fail if it's not.
+
+  * Added support for `--verbosity=error` and `--verbosity=warning`.
+
+  * `pub serve` now collapses multiple GET requests into a single line of
+    output. For full output, use `--verbose`.
+
+  * `pub deps` has improved formatting for circular dependencies on the
+    entrypoint package.
+
   * `pub run` and `pub global run`
 
+    * **Breaking:** to match the behavior of the Dart VM, executables no longer
+      run in checked mode by default. A `--checked` flag has been added to run
+      them in checked mode manually.
+
     * Faster start time for executables that don't import transformed code.
 
     * Binstubs for globally-activated executables are now written in the system
       encoding, rather than always in `UTF-8`. To update existing executables,
       run `pub cache repair`.
 
   * `pub get` and `pub upgrade`
 
     * Pub will now generate a ".packages" file in addition to the "packages"
       directory when running `pub get` or similar operations, per the
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     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.