Update Web NFC flag expiration

Change-Id: I64b768922a16decf60df57006cbd93a6f9a677b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1920669
Auto-Submit: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Rijubrata Bhaumik <rijubrata.bhaumik@intel.com>
Commit-Queue: Rijubrata Bhaumik <rijubrata.bhaumik@intel.com>
Cr-Commit-Position: refs/heads/master@{#716120}

chrome/browser/flag-metadata.json

@@ -2084,7 +2084,7 @@
   {
     "name": "enable-webnfc",
     "owners": [ "rijubrata.bhaumik@intel.com","reillyg" ],
-    "expiry_milestone": 79
+    "expiry_milestone": 82
   },
   {
     "name": "enable-webrtc-hide-local-ips-with-mdns",