✨ add cache system to improve perfs on google keys fetching

[ripoul]

No description provided.

[Copilot]

Pull request overview

This PR introduces a caching system to improve performance when fetching Google's signing keys for webhook validation. The cache is optional and allows users to provide their own cache backend implementation to avoid repeated HTTP requests to Google's key endpoint.

Key Changes:

• Added a flexible cache abstraction with CacheInterface and CacheConfig classes
• Integrated cache support into the Validator class with fallback to HTTP fetch
• Added comprehensive test coverage for cache hit, miss, and invalid data scenarios

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
google_wallet_webhook_auth/cache.py	Introduces new CacheInterface abstract class and CacheConfig dataclass for cache configuration
google_wallet_webhook_auth/validator.py	Adds optional cache_config parameter and implements cache check/store logic in _get_google_key()
tests/test_validator.py	Adds three new test cases covering cache hit, miss, and invalid cached data scenarios
README.md	Documents cache usage with a Django example implementation
pyproject.toml	Updates version from 0.1.0 to 1.0.0
uv.lock	Reflects the version bump in the lock file

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.