Pick up TS 2.6.2

Fixes #39206

extensions/package.json

@@ -3,7 +3,7 @@
   "version": "0.0.1",
   "description": "Dependencies shared by all extensions",
   "dependencies": {
-    "typescript": "2.6.2-insiders.20171120"
+    "typescript": "2.6.2"
   },
   "scripts": {
     "postinstall": "node ./postinstall"

extensions/yarn.lock

@@ -2,6 +2,6 @@
 # yarn lockfile v1
 
 
-typescript@2.6.2-insiders.20171120:
-  version "2.6.2-insiders.20171120"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.6.2-insiders.20171120.tgz#d2f4c36831fa663639624799a62814cbdca9aaae"
+typescript@2.6.2:
+  version "2.6.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.6.2.tgz#3c5b6fd7f6de0914269027f03c0946758f7673a4"