[FND-3] Release 7.0.0

[lucassus]

This pull request updates the maxio-advanced-billing-sdk to version 7.0.0, revises documentation, and introduces minor enhancements to the SDK. The most important changes include upgrading dependencies, updating references to version 7.0.0 across documentation, and adding utility methods in the SDK.

SDK Version Upgrade:

• Updated the maxio-advanced-billing-sdk version from 6.1.0 to 7.0.0 in advanced_billing.gemspec, including dependency updates (apimatic_core updated to ~> 0.3.17). [1] [2]

Documentation Updates:

• Updated all references in README.md and other documentation files to reflect version 7.0.0, including links to new API documentation and SDK features. [1] [2] [3]
• Added puts result statements to example API calls in doc/controllers/advance-invoice.md and doc/controllers/api-exports.md for better clarity in usage examples. [1] [2] [3] [4]

New Utility Methods:

• Introduced the ApiHelper class with methods like json_deserialize and rfc3339 for JSON parsing and DateTime handling in doc/api-helper.md.

Minor Enhancements:

• Improved parameter descriptions in doc/controllers/api-exports.md for better readability.

These changes ensure the SDK is up-to-date, improve developer experience, and introduce minor enhancements to the documentation and utilities.

[mykhi]

🚢