Add Dependabot schedule day, time, and timezone options

[Wanbinyu]

What's changed?

• Add optional day, time, and timezone options to ChangeDependabotScheduleInterval while retaining the existing two-argument constructor.
• Update or insert configured schedule fields for every matching package ecosystem, leaving optional fields unchanged when their recipe option is omitted.
• Preserve existing scalar formatting and comments, insert missing fields in Dependabot schedule order, and normalize flow mappings only when new fields must be added.
• Regenerate recipes.csv and add coverage for matching/non-matching ecosystems, multiple update entries, existing/missing fields, null options, comments, ordering, .yml/.yaml, declarative configuration, flow mappings, and idempotency.

What's your motivation?

Allow users to configure the full Dependabot schedule supported by the existing recipe.

• Fixes ChangeDependabotScheduleInterval - Add option to configure the schedule #54

Testing

• ./gradlew.bat --no-daemon test --tests org.openrewrite.github.ChangeDependabotScheduleIntervalTest
• ./gradlew.bat recipeCsvGenerate
• ./gradlew.bat recipeCsvValidate
• ./gradlew.bat --no-daemon clean build
• git diff --check

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've run ./gradlew build locally, and committed any resulting changes to recipes.csv
• I've formatted the lines I changed, without reformatting code I didn't touch

[greg-at-moderne]

Thanks for the quality contribution. I have made some amendments to this PR:

• coverage for empty schedule
• coverage for (rather rare, but still) so called flow-syntax, e.g.

              updates:
                - { package-ecosystem: github-actions, directory: /, schedule: { interval: daily } }