Change socket mode ping/pong from debug to trace

[bruceadowns]

The following messages are better served as trace rather than debug.

• Checking the current session...
• The session maintenance completed
• Sending a ping message
• Received a pong message

Turning on debug is helpful is understanding the associated request/response, but cannot be left on due to these periodic trace messages.

ref
https://github.com/slackapi/java-slack-sdk/blob/main/slack-api-client/src/main/java/com/slack/api/socket_mode/SocketModeClient.java#L188-L190

Category (place an x in each of the [ ])

• bolt (Bolt for Java)
• bolt-{sub modules} (Bolt for Java - optional modules)
• slack-api-client (Slack API Clients)
• slack-api-model (Slack API Data Models)
• slack-api-*-kotlin-extension (Kotlin Extensions for Slack API Clients)
• slack-app-backend (The primitive layer of Bolt for Java)

Requirements

Please make sure if this topic is specific to this SDK. For general questions/issues about Slack API platform or its server-side, could you submit questions at https://my.slack.com/help/requests/new instead. 🙇

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[bruceadowns]

If the maintainers agree, I can post a PR.

[seratch]

Thanks for the suggestion! Yes, this makes sense, so we're happy to have the change.