feat: add a generic API request interface (#374)

# Description

Adds a generic API request interface to make arbitrary API requests.

# Testing

- New unit test added for the generic API request interface
- All tests passing

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Co-authored-by: Claude Sonnet 4.5 <[email protected]>

feat: delete tracker (#373)

Co-authored-by: Claude Sonnet 4.5 <[email protected]>

Merge pull request #370 from EasyPost/EXP-761_stateless_rate_deserial…

…izer

fix: StatelessRateDeserializer and WebhookDeserializer for underscore fields

Merge pull request #367 from EasyPost/feature/fedex-2fa-support

feat(fedex): add FedEx Multi-Factor Authentication endpoints

Merge pull request #365 from EasyPost/v8.4.1

chore: prep v8.4.1

Merge pull request #363 from EasyPost/v8.4.0

chore: prep v8.4.0

Merge pull request #359 from EasyPost/SHPE-484_verify_carrier

feat: add verify_carrier address param

Merge pull request #353 from EasyPost/luma

feat: adds luma functions

Merge pull request #352 from EasyPost/claim_reference

feat: adds reference to claims

Merge pull request #351 from EasyPost/ups_endpoint

fix: endpoint used for UPS create/update