Fixes #4579

Summary

This PR adds license detection support for PlantUML's unique multi-license structure, where users can choose from MIT, Apache-2.0, EPL-2.0, LGPL-3.0+, or GPL-3.0+.

Changes

• Added plantuml_1.RULE: New license detection rule that identifies PlantUML's license notice from their README, capturing the full disjunctive license expression (mit OR apache-2.0 OR epl-2.0 OR lgpl-3.0-plus OR gpl-3.0-plus)
• Added false-positive-plantuml_1.RULE: False positive rule to prevent incorrect GPL-2. 0 detection from PlantUML's Javadoc badge URL that contains "gplv2" in the path
• Added test case: plantuml_license_notice.txt and corresponding .yml file to validate the detection rule

Testing

Included data-driven test case in tests/licensedcode/data/datadriven/lic4/ to ensure accurate detection of PlantUML's multi-license notice.

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled and links the original issue above
• Tests pass -- look for a green checkbox a few minutes after opening your PR
  Run tests locally to check for errors.
• Commits are in uniquely-named feature branch and has no merge conflicts
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst (if applicable)