Set the SDGym Slack alert to be posted on the `sdgym` channel.

[R-Palazzo]

Problem Description

Currently, results alerts from SDGym are sent to the sdv-alert Slack channel. We want to update this to the more appropriate sdgym Slack channel.

Expected behavior

Update the slack channel to be sdgym:

SDGym/sdgym/run_benchmark/utils.py

Line 15 in 80e8e1f

SLACK_CHANNEL = 'sdv-alerts'