Change default polling_interval to 1 sec

[hachi8833]

I think the current polling_interval: 0.1 for queue.yml is too aggressive so I'm sending the following PR to make the default less aggressive:

# lib/generators/solid_queue/install/templates/config/queue.yml
     - queues: "*"
       threads: 3
       processes: <%%= ENV.fetch("JOB_CONCURRENCY", 1) %>
-      polling_interval: 0.1
+      polling_interval: 1

Actually I encountered several race-conditions with the polling_interval: 0.1 when querying the DB (SQLite3) from my dashboard in fly.io.

Hope this change would be helpful for future users 🙏