[release] package.json: require vscode 1.46 or up

The recent change (https://go-review.googlesource.com/c/vscode-go/+/245127)
uses an API that's available only from 1.46. So, this extension
requires at least 1.46. Earlier versions of VS code will refuse
to install the new extension and remain with the last version.

Also, update vscode-languageclient to 6.1.3

Change-Id: I4039a1b882ccd59ad5d16d142bbf49f26e793d37
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/245638
Reviewed-by: Rebecca Stambler <[email protected]>
(cherry picked from commit fe3c6b5)
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/245641
Reviewed-by: Brayden Cloud <[email protected]>
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>

Author: hyangah

package-lock.json

@@ -55,7 +55,7 @@
     "tree-kill": "file:third_party/tree-kill",
     "vscode-debugadapter": "^1.40.0",
     "vscode-debugprotocol": "^1.40.0",
-    "vscode-languageclient": "6.1.0",
+    "vscode-languageclient": "^6.1.3",
     "web-request": "^1.0.7"
   },
   "devDependencies": {
@@ -83,7 +83,7 @@
     "yarn": "^1.22.4"
   },
   "engines": {
-    "vscode": "^1.41.0"
+    "vscode": "^1.46.0"
   },
   "activationEvents": [
     "workspaceContains:**/*.go",