Remove junov from remaining OWNERS and adding fserb

adding fserb to:
- imagebitmap
- core

Change-Id: I1598799a8e4837685880ac09dcbf4afb2f6091c3
Reviewed-on: https://chromium-review.googlesource.com/c/1297395Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602324}

third_party/blink/renderer/core/OWNERS

@@ -26,6 +26,7 @@ fmalita@chromium.org
 # foolip reviews <video>, <track>, WebVTT and Fullscreen.
 foolip@chromium.org
 fs@opera.com
+fserb@chromium.org
 futhark@chromium.org
 haraken@chromium.org
 hayato@chromium.org
@@ -37,7 +38,6 @@ jbroman@chromium.org
 jfernandez@igalia.com
 jianli@chromium.org
 jochen@chromium.org
-junov@chromium.org
 kbr@chromium.org
 keishi@chromium.org
 kenneth.r.christiansen@intel.com

third_party/blink/renderer/core/html/canvas/OWNERS

 fserb@chromium.org
-junov@chromium.org
-xlai@chromium.org
 
 # TEAM: paint-dev@chromium.org
 # COMPONENT: Blink>Canvas

third_party/blink/renderer/core/imagebitmap/OWNERS

-junov@chromium.org
+fserb@chromium.org
 zakerinasab@chromium.org
 
 # TEAM: paint-dev@chromium.org

third_party/blink/renderer/modules/canvas/OWNERS

 fserb@chromium.org
-junov@chromium.org
 # canvas, imagebitmap
 senorblanco@chromium.org
 # lowLatency

third_party/blink/renderer/platform/OWNERS

@@ -7,7 +7,6 @@ fserb@chromium.org
 haraken@chromium.org
 jbroman@chromium.org
 jochen@chromium.org
-junov@chromium.org
 kbr@chromium.org
 kinuko@chromium.org
 mkwst@chromium.org

third_party/blink/renderer/platform/graphics/OWNERS

@@ -5,7 +5,6 @@ flackr@chromium.org
 fmalita@chromium.org
 fserb@chromium.org
 jbroman@chromium.org
-junov@chromium.org
 kbr@chromium.org
 pdr@chromium.org
 schenney@chromium.org