Refactor transition_data variable names for consistency

[sTomerG]

⚠️ breaking change

closes #2

This pull request updates the naming of the transition_data variable to transitions_data across multiple files to ensure consistency with the class name and improve code readability. The changes affect the following files:

• README.md: Updated variable names in usage examples.
• docs/examples/example_many.py: Adjusted variable names in the examples.
• tz_canary/infer.py: Refactored function arguments and internal variable names.
• tz_canary/transitions_data.py: Adjusted variable references in class instantiation and examples.
• tz_canary/validate.py: Updated function arguments and logic for validating time zones.