Update milestone for storage-access-api flag.

Bug: 989663
Change-Id: I3bdc8f4996905c9e57ba2fabc86dfe53301e2ba1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2032051
Commit-Queue: Brandon Maslen <brandm@microsoft.com>
Commit-Queue: Eric Lawrence [MSFT] <ericlaw@microsoft.com>
Auto-Submit: Brandon Maslen <brandm@microsoft.com>
Reviewed-by: Eric Lawrence [MSFT] <ericlaw@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#737137}

chrome/browser/flag-metadata.json

@@ -3394,7 +3394,7 @@
   {
     "name": "storage-access-api",
     "owners": [ "brandm@microsoft.com" ],
-    "expiry_milestone": 80
+    "expiry_milestone": 85
   },
   {
     "name": "strict-origin-isolation",