[release] package.json: update the version for v0.40.2 release

Change-Id: I2d8b818aae4abed83dc685f3f9f2e2713e924879
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/556861
Reviewed-by: Robert Findley <[email protected]>
Commit-Queue: Hyang-Ah Hana Kim <[email protected]>
TryBot-Result: kokoro <[email protected]>

Author: hyangah

package-lock.json

@@ -1,7 +1,7 @@
 {
   "name": "go",
   "displayName": "Go",
-  "version": "0.40.1",
+  "version": "0.40.2",
   "publisher": "golang",
   "description": "Rich Go language support for Visual Studio Code",
   "author": {