feat(turbo.json): allow for trailing commas (#10537)
### Description
Fixes #10499
### Testing Instructions
```
[0 olszewski@macbookpro] /tmp/trailing $ turbo build
turbo 2.5.4-canary.0
turbo_json_parse_error
× Failed to parse turbo.json.
╰─▶ × Expected a property but instead found '}'.
╭─[turbo.json:9:5]
8 │ "outputs": [".next/**", "!.next/cache/**"],
9 │ },
· ─
10 │ "lint": {
╰────
[1 olszewski@macbookpro] /tmp/trailing $ turbo_dev --skip-infer build
turbo 2.5.4
• Packages in scope: @repo/eslint-config, @repo/typescript-config, @repo/ui, docs, web
• Running build in 5 packages
• Remote caching disabled
```
