Change cp command to copy for Windows compatibility

Author: yuseok-kim-edushare

.github/workflows/cd.yaml

@@ -90,7 +90,7 @@ jobs:
         
     - name: Copy app.config to release-files
       run: |
-        cp ${{ github.workspace }}\app.config ${{ github.workspace }}\release-files\net48\app.config
+        copy ${{ github.workspace }}\app.config ${{ github.workspace }}\release-files\net48\app.config
 
     - name: Create Release
       uses: softprops/action-gh-release@v2