Adds katie@chromium.org to a11y watchlists

BUG=none
NOTRY=true

Change-Id: I78b082eae5c8033dee3bc2684a8d176034d7857e
Reviewed-on: https://chromium-review.googlesource.com/811687Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522188}

WATCHLISTS

@@ -1609,6 +1609,7 @@
                       'dougt+watch@chromium.org',
                       'dtseng+watch@chromium.org',
                       'je_julie.kim@chromium.org',
+                      'katie+watch@chromium.org',
                       'nektar+watch@chromium.org',
                       'yuzo+watch@chromium.org'],
     'add_to_homescreen': ['dominickn+watch@chromium.org',
@@ -1694,6 +1695,7 @@
                             'dmazzoni@chromium.org',
                             'dougt+watch@chromium.org',
                             'je_julie.kim@chromium.org',
+                            'katie+watch@chromium.org',
                             'nektar@chromium.org'],
     'blink_animation': ['alexis.menard@intel.com',
                         'blink-reviews-animation@chromium.org',