Update config.yml

[erictleung]

Remove dangling square bracket.

Description

I made a PR recently #7960 and noticed the welcome message had a dangling square bracket.

So this PR removes that so that things render correctly.

Related Issue

• [ ] Closes #
• [ ] Related to #

Checklist

• [X] Checked that the pre-commit linting/style checks pass
• [X] Included tests that prove the fix is effective or that the new feature works
• [X] Added necessary documentation (docstrings and/or example notebooks)
• [X] If you are a pro: each commit corresponds to a relevant logical change

Type of change

• [ ] New feature / enhancement
• [ ] Bug fix
• [ ] Documentation
• [X] Maintenance
• [ ] Other (please specify):