Updated .clabot to fix invalid JSON from trailing comma

[syntax-tm]

Pull request type

Please check the type of change your PR introduces:

• Update
• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes

What is the current behavior?

Currently the clabot errors out parsing the JSON (ERROR The .clabot file is not valid JSON).

2023-09-21T07:05:48.685Z INFO Checking CLAs for pull request https://api.github.com/repos/lepoco/wpfui/pulls/767
2023-09-21T07:05:48.685Z INFO Bot installed as an integration, obtaining installation token
2023-09-21T07:05:48.687Z INFO API Request https://api.github.com/app/installations/33815071/access_tokens
2023-09-21T07:05:48.760Z INFO Obtaining the list of commits for the pull request
2023-09-21T07:05:48.760Z INFO API Request https://api.github.com/repos/lepoco/wpfui/pulls/767/commits
2023-09-21T07:05:48.918Z INFO Total Commits: 1, checking CLA status for committers
2023-09-21T07:05:48.918Z INFO Attempting to obtain organisation level .clabot file URL
2023-09-21T07:05:48.918Z INFO API Request https://api.github.com/repos/lepoco/clabot-config/contents/.clabot
2023-09-21T07:05:48.999Z INFO Organisation configuration not found, resolving .clabot URL at project level
2023-09-21T07:05:48.999Z INFO API Request https://api.github.com/repos/lepoco/wpfui/contents/.clabot
2023-09-21T07:05:49.139Z INFO Obtaining .clabot configuration file from https://raw.githubusercontent.com/lepoco/wpfui/main/.clabot
2023-09-21T07:05:49.139Z INFO API Request https://raw.githubusercontent.com/lepoco/wpfui/main/.clabot
2023-09-21T07:05:49.367Z ERROR The .clabot file is not valid JSON
2023-09-21T07:05:49.367Z INFO API Request https://api.github.com/repos/lepoco/wpfui/statuses/771c692828a7d8387a040cbe0fcd814a350c997d
2023-09-21T07:05:49.727Z ERROR Error: The .clabot file is not valid JSON

Issue Number: N/A

What is the new behavior?

The file should be valid JSON now so hopefully the clabot quits complaining about it.

Other information

I realize this PR is for main, but this is intentional because the .clabot file used by the bot is the one on main.