ci: add postrelease workflow to update docs and release winget packages (#1983)

(cherry picked from commit c61d5dd5c631a173d691121ebc6c7d4ec7279218)

.github/workflows/postrelease.yml

@@ -1,13 +1,17 @@
-name: Publish to winget
+name: Postrelease
 on:
   release:
     types: [released]
 
 jobs:
-  publish:
+  postrelease:
     if: ${{ github.repository == 'lite-xl/lite-xl' && startsWith(github.ref, 'refs/tags/v') }}
     runs-on: windows-latest
     steps:
+      - name: Update winget-pkgs repository
+        env: { GH_TOKEN: "${{ secrets.WINGET_TOKEN }}" }
+        run: gh repo sync lite-xl/winget-pkgs
+
       - name: Release to winget
         uses: vedantmgoyal9/winget-releaser@main
         with: