Add configurable Monolog field name

[pforesi]

Add configurable Monolog field name

Description

This PR adds the ability to customize the field name used in Monolog's extra array to store the request ID. Previously, the field name was hardcoded as request_id.

What's Changed

New Configuration Option

• Added monolog_field_name configuration parameter (defaults to request_id for backward compatibility)
• The field name is exposed as a container parameter %chrisguitarguy_request_id.monolog_field_name%

Benefits

• Flexibility: Users can now customize the field name to match their logging conventions
• No duplication: The container parameter can be referenced in service definitions (e.g., Monolog formatters)
• Backward compatible: Default value maintains existing behavior

Usage Example

Basic usage (default behavior)

chrisguitarguy_request_id:
    enable_monolog: true
    # monolog_field_name: request_id  # default value
Custom field name with container parameter
chrisguitarguy_request_id:
    monolog_field_name: my_request_id

services:
    custom_formatter:
        class: Monolog\Formatter\LineFormatter
        arguments:
            # Uses the container parameter - no duplication needed!
            - "[%%level_name%% - %%extra.%chrisguitarguy_request_id.monolog_field_name%%%] %%message%%"

Testing

✅ All existing tests pass (24 tests, 65 assertions)
✅ Added 2 new unit tests for custom field names (Monolog v1-2 and v3+)
✅ Added acceptance test to verify container parameter is correctly defined
✅ No breaking changes
Documentation
Updated README.md with configuration details and usage examples
Updated CHANGELOG.md with the new features
Added inline code documentation
Checklist
Code follows project style guidelines
Tests added for new functionality
Documentation updated
Backward compatible
All tests passing