[base] Add LON scheduling team to base/task/OWNERS

Add alexclarke@, altimin@ and skyostil@ to base/task/OWNERS as base/task
now contains all base task scheduling infrastructure.

Also update component tagging:
- base/task: Internals>TaskScheduling
- base/task/sequence_manager: Internals>SequenceManager

R=gab@chromium.org,fdoray@chromium.org
CC=alexclarke@chromium.org,skyostil@chromium.org

Change-Id: I0a92c5d67630774d932ea109de896c5764c30301
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1605904Reviewed-by: François Doray <fdoray@chromium.org>
Commit-Queue: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659213}

base/task/OWNERS

 fdoray@chromium.org
 gab@chromium.org
 robliao@chromium.org
+alexclarke@chromium.org
+altimin@chromium.org
+skyosti@lchromium.org
 
 # TEAM: scheduler-dev@chromium.org
-# COMPONENT: Internals>ThreadPool
+# COMPONENT: Internals>TaskScheduling

base/task/sequence_manager/OWNERS

@@ -3,4 +3,4 @@ alexclarke@chromium.org
 skyostil@chromium.org
 
 # TEAM: scheduler-dev@chromium.org
-# Component: Blink>Scheduling
+# Component: Internals>SequenceManager