ci: Bump actions/upload-artifact from v3 to v4

Author: sgryjp

.github/workflows/ci.yml

@@ -50,7 +50,7 @@ jobs:
 
       - run: npm install --global vsce
       - run: vsce package
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: "VSIX file"
           path: |