Update DEPS to latest linter (0.1.26).

Update DEPS to latest linter (0.1.26).

* Updated tests to use package `test` (#302).
* Fixed false positive on `[]=` in `always_declare_return_types` (#300).
* New `invariant_booleans` lint.
* New `literal_only_boolean_expressions` lint.
* Fixed `camel_case_types` to allow `$` in identifiers (#290).

BUG=
R=brianwilkerson@google.com

Committed: https://github.com/dart-lang/sdk/commit/45a4ae042b8901e82061d2cd3f965201dbd05445

[pquitslund, 2016-09-05 19:00:54]

pquitslund@google.com changed reviewers:
+ brianwilkerson@google.com

[Brian Wilkerson, 2016-09-06 13:47:29]

lgtm

[pquitslund, 2016-09-06 23:39:41]

Description was changed from

==========
Update DEPS to latest linter (0.1.26).

* Updated tests to use package `test` (#302).
* Fixed false positive on `[]=` in `always_declare_return_types` (#300).
* New `invariant_booleans` lint.
* New `literal_only_boolean_expressions` lint.
* Fixed `camel_case_types` to allow `$` in identifiers (#290).

BUG=
==========

to

==========
Update DEPS to latest linter (0.1.26).

* Updated tests to use package `test` (#302).
* Fixed false positive on `[]=` in `always_declare_return_types` (#300).
* New `invariant_booleans` lint.
* New `literal_only_boolean_expressions` lint.
* Fixed `camel_case_types` to allow `$` in identifiers (#290).

BUG=
R=brianwilkerson@google.com

Committed:
https://github.com/dart-lang/sdk/commit/45a4ae042b8901e82061d2cd3f965201dbd05445
==========

[pquitslund, 2016-09-06 23:39:43]

Committed patchset #1 (id:1) manually as
45a4ae042b8901e82061d2cd3f965201dbd05445 (presubmit successful).