DEPS bump to pull in linter 0.1.22.

Linter `0.1.22`.

* Grinder support (`rule:rule_name` and `docs:location`) for rule stub and doc generation (respectively).
* Fix to allow leading underscores in `non_constant_identifier_names`.
* New `valid_regexps` lint (#277).
* New `whitespace_around_ops` lint (#249).
* Fix to `overridden_fields` to flag overridden static fields (#274).
* New `list_remove_unrelated_type` to detect passing a non-`T` value to `List.remove()`` (#271).
* New `empty_catches` lint to catch empty catch blocks (#43).
* Fixed `close_sinks` false positive (#268).
* Added `linter` support for `--strong` to allow for running linter in strong mode.

BUG=
R=brianwilkerson@google.com, scheglov@google.com

Review URL: https://codereview.chromium.org/2185833004 .

Author: pq

DEPS

@@ -71,7 +71,7 @@ vars = {
   "isolate_tag": "@0.2.2",
   "jinja2_rev": "@2222b31554f03e62600cd7e383376a7c187967a1",
   "json_rpc_2_tag": "@2.0.0",
-  "linter_rev": "@7ca3aab6ca45b988440e425c187993a533fbe27e",
+  "linter_rev": "@4b4f1f237914fbfbb4e3850bd648a70cc0ce8e15",
   "logging_rev": "@85d83e002670545e9039ad3985f0018ab640e597",
   "markdown_rev": "@4aaadf3d940bb172e1f6285af4d2b1710d309982",
   "matcher_tag": "@0.12.0",