.github/workflows: fix release.yml to use npx vsce for packaging

Updates #2676

Change-Id: Idba55e5976bf85e587a4cef04773c15114446087
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/470975
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Suzy Mueller <suzmue@golang.org>

Author: hyangah

.github/workflows/release.yml

@@ -80,10 +80,8 @@ jobs:
           npm ci
           npm run vscode:prepublish
 
-      - name: package
-        uses: lannonbr/vsce-action@0f3391ee0477b08fae949eb0a875e91e6d20b075
-        with:
-          args: "package"
+      - name: package extension
+        run: npx vsce package -o "./go-${{ env.EXT_VERSION }}.vsix"
 
       - name: create release
         id: create_release
@@ -108,6 +106,6 @@ jobs:
 
       - name: publish
         if: env.EXT_ISPREVIEW != 1 && github.repository == 'golang/vscode-go'
-        run: npx vsce publish -i "./go-nightly-${{ env.VSCODE_GO_VERSION }}.vsix" -p "${{ secrets.VSCE_TOKEN }}"
+        run: npx vsce publish -i "./go-${{ env.EXT_VERSION }}.vsix" -p "${{ secrets.VSCE_TOKEN }}"
 
 # TODO: check if the commit is in green state. (test-long.yml results)