Update tree-sitter requirement from 0.19 to 0.20 in /ruby/extractor

Updates the requirements on [tree-sitter](https://github.com/tree-sitter/tree-sitter) to permit the latest version.
- [Release notes](https://github.com/tree-sitter/tree-sitter/releases)
- [Commits](tree-sitter/tree-sitter@v0.19.0...v0.20.6)

---
updated-dependencies:
- dependency-name: tree-sitter
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]