Updated sleep command to fix local-e2e tests (#1785)

- local e2e tests were failing on macOS because of improper usage of the `sleep` command
- on macOS, the `sleep` command does not accept a suffix (e.g. `s`, `m`, `h`) — only an integer value of seconds is allowed

.github/workflows/local-e2e-test.yml

@@ -30,5 +30,5 @@ jobs:
       - name: Setting up Ghost instance
         run: node ./cli/bin/ghost install local -d ghost
       - name: Verifying Installation
-        run: sleep 2s && curl -f http://localhost:2368 | grep ghost
+        run: sleep 2 && curl -f http://localhost:2368 | grep ghost