Bump dart_style to 0.2.10.

CHANGELOG.md

 ## 1.20.0
 
 ### Dart VM
 
 * We have improved the way that the VM locates the native code library for a
   native extension (e.g. `dart-ext:` import). We have updated this
   [article on native extensions](https://www.dartlang.org/articles/dart-vm/native-extensions)
   to reflect the VM's improved behavior.
 
 * Linux builds of the VM will now use the tcmalloc library for memory
   allocation. This has the advantages of better debugging and profiling support
   and faster small allocations, with the cost of slightly larger initial memory
   footprint, and slightly slower large allocations.
 
 * We have improved the way the VM searches for trusted root certificates for
   secure socket connections on Linux. First, the VM will look for trusted root
   certificates in standard locations on the file system
   (/etc/pki/tls/certs/ca-bundle.crt followed by /etc/ssl/certs), and only if
   these do not exist will it fall back on the builtin trusted root certificates.
   This behavior can be overridden on Linux with the new flags
   --root-certs-file and --root-certs-cache. The former is the path to a file
   containing the trusted root certificates, and the latter is the path to a
   directory containing root certificate files hashed using `c_rehash`.
 
 ### Core library changes
+
 * `dart:core`: Remove deprecated `Resource` class.
   Use the class in `package:resource` instead.
 * `dart:async`
   * `Future.wait` now catches synchronous errors and returns them in the
     returned Future.
   * More aggressively returns a Future on Stream.cancel operations.
     Discourages to return `null` from `cancel`.
   * Fixes a few bugs where the cancel future wasn't passed through
     transformations.
 * `dart:io`
@@ skipping 73 matching lines @@
 
 * Breaking change - ingore `dynamic` when doing inference.
 
     ```dart
     main() {
       dynamic d = 42;
       List<int> list = /*infer <int>*/[123, /*implicit cast*/d];
     }
     ```
 
+### Tool changes
+
+* `dartfmt` - upgraded to v0.2.10
+    * Don't crash on annotations before parameters with trailing commas.
+    * Always split enum declarations if they end in a trailing comma.
+    * Add `--set-exit-if-changed` to set the exit code on a change.
+
 ## 1.19.0
 
 ### Language changes
 
 * The language now allows a trailing comma after the last argument of a call and
  the last parameter of a function declaration. This can make long argument or
  parameter lists easier to maintain, as commas can be left as-is when
  reordering lines. For details, see SDK issue
  [26644](https://github.com/dart-lang/sdk/issues/26644).
 
@@ skipping 1185 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.