Add support for open-test-reporting format

Add a new parser for the open-test-reporting format developed by the
JUnit team (https://github.com/ota4j-team/open-test-reporting).

This format is a modern, framework-agnostic XML-based test reporting
standard that supports rich metadata including tags, attachments, and
infrastructure information.

Features:
- Auto-detection of both XML format variants:
  - Hierarchical format (h:execution) - tree-structured results
  - Event-based format (e:events) - streaming/real-time results
- ISO 8601 duration parsing (e.g., PT1.234S)
- Status mapping: SUCCESSFUL, SKIPPED, ABORTED, FAILED, ERRORED
- Error message extraction from failed tests
- Proper XML namespace handling

Files added:
- src/parsers/open-test-reporting/open-test-reporting-types.ts
- src/parsers/open-test-reporting/open-test-reporting-parser.ts
- __tests__/open-test-reporting.test.ts (20 tests)
- __tests__/fixtures/open-test-reporting/*.xml

action.yml

@@ -32,6 +32,7 @@ inputs:
         - java-junit
         - jest-junit
         - mocha-json
+        - open-test-reporting
         - python-xunit
         - rspec-json
         - swift-xunit