Add Open VSX namespace creation step to release workflow

Author: tebjan

.github/workflows/release.yml

@@ -74,6 +74,10 @@ jobs:
         env:
           VSCE_PAT: ${{ secrets.VS_MARKETPLACE_TOKEN }}
 
+      - name: Ensure Open VSX namespace exists
+        working-directory: VSCode/vscode-extension
+        run: npx ovsx create-namespace stride -p ${{ secrets.OPEN_VSX_TOKEN }} || true
+
       - name: Publish to Open VSX Registry
         working-directory: VSCode/vscode-extension
         run: |