ci: test against Redis 8 in CI workflow

- Add Redis version 8 to the test matrix in the GitHub Actions workflow

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

feat: unify store initialization with flexible option-based API (#92)

* feat: unify store initialization with flexible option-based API

- Replace legacy initialization functions with a unified NewStore() using the Option Pattern
- Add extensive configuration options for connection, authentication, Redis, and session settings
- Implement strict validation for configuration and connection options at initialization
- Remove code duplication and improve separation of concerns in store setup
- Update documentation and usage examples for the new API
- Add a comprehensive migration guide for upgrading from v1 to v2
- Update module path to github.com/boj/redistore/v2 for semantic versioning
- Improve error messages and fail-fast behavior for invalid configurations
- Add a new test suite with thorough coverage for option validation and error handling
- Deprecate v1 API and document migration steps
- Enhance developer experience with clearer, more flexible, and self-documenting options

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* refactor: refactor error handling and option selection logic

- Refactor error construction to use multiline return statements for clarity
- Replace if-else chains with a switch statement for connection option selection
- Update tests to build expected error strings in multiple lines for consistency with implementation

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* feat: refactor key management to support key rotation and helpers

- Change NewStore to accept key pairs as [][]byte instead of []byte, enabling proper support for key rotation
- Add Keys and KeysFromStrings helper functions for easier key pair creation
- Update documentation and migration guides to reflect the new key pairs format and usage
- Add detailed examples and explanations for key rotation and helper usage
- Update all code and tests to use the new key pairs format and helpers
- Add tests for key rotation and the new helper functions

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* Update redistore.go

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* refactor: refactor Redis error handling to use shared constants

- Refactor repeated Redis connection error strings into constants for improved maintainability
- Update tests to use the new error constants instead of hardcoded error messages

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

---------

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

chore: refactor codebase for improved maintainability

- No changes detected in the provided diff.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

ci: update CI workflows and tests for better compatibility

- Update the job name to include Redis version in GitHub Actions workflow

Signed-off-by: appleboy <appleboy.tw@gmail.com>

docs: refactor codebase for improved performance and maintainability

- Add an empty string parameter to the `redistore.NewRediStore` function call in `README.md`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

refactor: refactor codebase to improve performance and maintainability

- Remove redundant variable redeclaration of `cookies` in `TestRediStore` function

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

maintenance tag release

current version is fairly stable, so we'll start with gopkg.in at v1