Add link to downloadable zip to playground output

.github/workflows/playground.yml

@@ -13,4 +13,4 @@ jobs:
         with:
           message: |
             **Test on Playground**
-            [Test this pull request on the Playground](https://playground.wordpress.net/#{"landingPage":"/wp-admin/edit-tags.php?taxonomy=post_tag","features":{"networking":true},"steps":[{"step":"defineWpConfigConsts","consts":{"IS_PLAYGROUND_PREVIEW":true}},{"step":"login","username":"admin","password":"password"},{"step":"installPlugin","pluginZipFile":{"resource":"url","url":"https://bypass-cors.altha.workers.dev/${{ github.server_url }}/${{ github.repository }}/archive/${{ github.sha }}.zip"},"options":{"activate":true}}]})
+            [Test this pull request on the Playground](https://playground.wordpress.net/#{"landingPage":"/wp-admin/edit-tags.php?taxonomy=post_tag","features":{"networking":true},"steps":[{"step":"defineWpConfigConsts","consts":{"IS_PLAYGROUND_PREVIEW":true}},{"step":"login","username":"admin","password":"password"},{"step":"installPlugin","pluginZipFile":{"resource":"url","url":"https://bypass-cors.altha.workers.dev/${{ github.server_url }}/${{ github.repository }}/archive/${{ github.sha }}.zip"},"options":{"activate":true}}]}) or [download the zip](${{ github.server_url }}/${{ github.repository }}/archive/${{ github.sha }}.zip)