Preparations for release of preview version 3

[michelebastione]

• Renamed the MappingTemplater's ApplyTemplateAsync method overloads to FillTemplateAsync for keeping consistency with the OpenXmlTemplater respective methods' names
• Updated packages references and removed the superfluous Newtonsoft.Json one from the MiniExcel.Ope nXml.Tests test project
• Refactored benchmarks to be based off a 100,000 rows Excel file instead of a 1 million rows one, bringing their duration down from 6+ hours to 25 minutes.
• Fixed benchmark.yml workflow file and bumping project version
• Updated readmes and upgrade notes

[gemini-code-assist]

Code Review

This pull request updates several project dependencies, increments the version to 2.0.0-preview.3, and renames template-related methods from 'ApplyTemplate' to 'FillTemplate'. It also removes the Newtonsoft.Json dependency from the test projects, replacing it with System.Text.Json or manual object construction. Feedback is provided regarding the migration to System.Text.Json in 'TestIssue370', where deserializing to a dictionary results in 'JsonElement' values instead of primitives. This change necessitates manual parsing in assertions and reduces the test's effectiveness; it is recommended to define the test data directly to preserve type fidelity.

[michelebastione]

/gemini review

[gemini-code-assist]

Code Review

This pull request updates the project version to 2.0.0-preview.3, renames template-related methods from ApplyTemplate to FillTemplate (marking the old ones as obsolete), and significantly refactors the documentation and benchmarks. Feedback focuses on several critical compilation errors caused by the removal of required using statements for source generators and compiler services. Additionally, there is a missing dependency for ToListAsync() in tests, a logic error in a test assertion regarding decimal precision, and a minor formatting issue.