v0.5.1 — Python 3.9 compatibility + CI workflow

Patch release fixing two issues that surfaced immediately after v0.5.0
hit PyPI:

- 'pip install eupago' on Python 3.9 was importable but unusable — the
  first model instantiation crashed because Pydantic v2 can't evaluate
  'X | None' annotations on 3.9 without help. v0.5.0 shipped with the
  classifier claiming 3.9 support and no backport. v0.5.1 adds
  eval_type_backport as a conditional dep for Python <3.10.
- The CI badge in the README was pointing at a non-existent test.yml
  workflow. The workflow now exists and runs the standard gates across
  the full 3.9–3.13 matrix on push + PR.

README also re-aligned with the vendus-python sibling README structure
(bilingual docs link, bulleted Installation block with the PyPI URL)
so the two SDKs read consistently for anyone who finds one and looks
at the other.

Author: bilouro

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.1] - 2026-05-31
+
+### Fixed
+- **Python 3.9 compatibility**: added `eval_type_backport>=0.2` as a conditional dependency for Python <3.10. Without it, Pydantic v2 fails at model instantiation when evaluating `X | None` annotations on 3.9 (`TypeError: unsupported operand type(s) for |: 'type' and 'NoneType'`). v0.5.0 was published without this fix and was effectively unusable on 3.9 despite the classifier claiming support.
+- **CI workflow** (`.github/workflows/test.yml`) — was referenced by the README CI badge since day one but never existed. Now runs `ruff check`, `ruff format --check`, `mypy --strict` and `pytest -m "not integration"` on Python 3.9–3.13.
+- **README** aligned with the sibling `vendus` package: bilingual docs link ("English · Português"), Installation section as a bullet list with the explicit PyPI URL.
+
 ## [0.5.0] - 2026-05-31
 
 First production-validated release. MB WAY, Multibanco, Pay By Link and

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "eupago"
-version = "0.5.0"
+version = "0.5.1"
 description = "Unofficial Python SDK for the eupago payment gateway"
 readme = "README.md"
 requires-python = ">=3.9"

src/eupago/__init__.py

@@ -17,7 +17,7 @@
 )
 from eupago.models import Customer, PaymentResult, PaymentStatus, WebhookEvent
 
-__version__ = "0.5.0"
+__version__ = "0.5.1"
 
 __all__ = [
     "ApiError",