Update editor from a-sully@ to mingyc@ (#466)

Author: mingyc

index.bs

@@ -8,7 +8,8 @@ Abstract: This document extends the API in [[FS]] to enable developers to build
 Status: CG-DRAFT
 ED: https://wicg.github.io/file-system-access/
 Level: 1
-Editor: Austin Sullivan, Google, asully@chromium.org, w3cid 126126
+Editor: Ming-Ying Chung, Google, mych@chromium.org, w3cid 139196
+Former Editor: Austin Sullivan, Google, asully@chromium.org, w3cid 126126
 Former Editor: Marijn Kruisselbrink, Google, mek@chromium.org, w3cid 72440
 Group: WICG
 Repository: wicg/file-system-access