feat: add new MIME types supported by latest models

[Hugobsan]

New MIME Types Supported

Since the release of Gemini 2.0 Flash, several new MIME types have been supported. However, they were not yet added to the MimeType enum. Since building a FilePart for a request requires a valid MimeType enum instance, I decided to investigate.

After reviewing the official Gemini model documentation, I wrote a test script to try different file types and included all supported types in the enum.

Notes

Some MIME types like application/x-javascript and application/x-python were rejected by gemini-2.0-flash during testing. However, they have been preserved in the enum to maintain backwards compatibility with existing SDK users.

Output from my tests

MIME_Types_Test.csv

[Hugobsan]

• Added support for creating FilePart instances using MIME types or strings. This improves flexibility and prevents issues when new MIME types are introduced before the SDK is updated.
• Added newly released models to the ModelName enum, based on the official Gemini API documentation.