fix: updating FileList query field name (#1473)

renaming `items` (v2) to `files` (v3)

Author: sce-taid

drive/snippets/drive_v3/src/main/java/SearchFile.java

@@ -60,7 +60,7 @@ public static List<File> searchFile() throws IOException {
       FileList result = service.files().list()
           .setQ("mimeType='image/jpeg'")
           .setSpaces("drive")
-          .setFields("nextPageToken, items(id, title)")
+          .setFields("nextPageToken, files(id, title)")
           .setPageToken(pageToken)
           .execute();
       for (File file : result.getFiles()) {