Hv4gha

* Makes _pyproject.toml_ compatible with PEP 621 (https://github.com/andreaso/hv4gha/pull/42)
* Supports importing multiple versions of the "same" key (https://github.com/andreaso/hv4gha/pull/50)
* Switches to using the GitHub App's Client ID (https://github.com/andreaso/hv4gha/pull/51)
* Bumps certifi to 2024.12.14 (https://github.com/andreaso/hv4gha/pull/52)

* Promotes certifi to a direct dependency (https://github.com/andreaso/hv4gha/pull/28)
* Enforces keyword arguments for public methods (https://github.com/andreaso/hv4gha/pull/32)
* Bumps certifi requirement to 2024.7.4 (https://github.com/andreaso/hv4gha/pull/34)
* Bumps cryptography requirement to 43.0.1 (https://github.com/andreaso/hv4gha/pull/36)
* Bumps pydantic requirement to 2.8.0 (https://github.com/andreaso/hv4gha/pull/39)
* Adds support for Python 3.13 (https://github.com/andreaso/hv4gha/pull/40)

* Adds testing and support for Python 3.12 (21)

* Updates (slightly) vulnerable pyca/cryptography dependency (16)

* Opens up pyca/cryptography version requirement (6)
* Replaces unsupported datetime.strftime("%s") (9)
* Improved testing:
* Tests using both constrained and unconstrained dependencies (7)
* Adds pytest tests for helper functions (8, 12)

* Provides more detailed API error exceptions (3)
* Uses Pydantic to type check API responses (4)