Add Nova 3 and Keyterm support

[DamienDeepgram]

Proposed changes

Add Nova 3 & Keyterms Support

Types of changes

• Adding Nova 3 Model
• Adding Keyterm Feature

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update or tests (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING.md doc
• I have added tests and/or examples that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

Example Usage

Single Keyterm

let options = Options::builder()
        .model(Model::Nova3)
        .keyterms(["Acme"])
        .build();

Multiple Keyterms

let options = Options::builder()
        .model(Model::Nova3)
        .keyterms(["Acme", "Deepgram"])
        .build();

Keyterm Phrase

let options = Options::builder()
        .model(Model::Nova3)
        .keyterms(["Acme Labs"])
        .build();

[bd-g]

Let's bump the minor version here, since we're adding features. Looks great!

[thisislvca]

opened the same pr a few weeks ago hahah glad to see it added

[ashutoshxhq]

@bd-g waiting on the next release to use nova3