Bump allow-insecure-localhost flag expiration

Change-Id: Iafa21bda8d69d50dd5f78667ab6d21c616748fd4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2595514Reviewed-by: Carlos IL <carlosil@chromium.org>
Commit-Queue: Emily Stark <estark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837744}

chrome/browser/flag-metadata.json

@@ -71,7 +71,7 @@
   {
     "name": "allow-insecure-localhost",
     "owners": [ "security-dev" ],
-    "expiry_milestone": 87
+    "expiry_milestone": 95
   },
   {
     "name": "allow-previews",