chore(deps): update dependency astroid to v2.5.6

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
astroid	==2.5.2 -> ==2.5.6

---

Release Notes

PyCQA/astroid

### [`v2.5.6`](https://togithub.com/PyCQA/astroid/blob/master/ChangeLog#Whats-New-in-astroid-256) [Compare Source](https://togithub.com/PyCQA/astroid/compare/astroid-2.5.5...v2.5.6) ============================ Release Date: 2021-04-25 - Fix retro-compatibility issues with old version of pylint Closes [PyCQA/pylint#​4402](https://togithub.com/PyCQA/pylint/issues/4402) ### [`v2.5.5`](https://togithub.com/PyCQA/astroid/blob/master/ChangeLog#Whats-New-in-astroid-255) [Compare Source](https://togithub.com/PyCQA/astroid/compare/astroid-2.5.4...astroid-2.5.5) ============================ Release Date: 2021-04-24 - Fixes the discord link in the project urls of the package. Closes [PyCQA/pylint#​4393](https://togithub.com/PyCQA/pylint/issues/4393) ### [`v2.5.4`](https://togithub.com/PyCQA/astroid/blob/master/ChangeLog#Whats-New-in-astroid-254) [Compare Source](https://togithub.com/PyCQA/astroid/compare/astroid-2.5.3...astroid-2.5.4) ============================ Release Date: 2021-04-24 - The packaging is now done via setuptools exclusively. `doc`, `tests`, and `Changelog` are not packaged anymore - reducing the size of the package greatly. - Debian packaging is now (officially) done in . - `__pkginfo__` now only contain `__version__` (also accessible with `astroid.__version__`), other meta-information are still accessible with `import importlib;metadata.metadata('astroid')`. - Added inference tip for `typing.Tuple` alias - Fix crash when evaluating `typing.NamedTuple` Closes [PyCQA/pylint#​4383](https://togithub.com/PyCQA/pylint/issues/4383) - COPYING was removed in favor of COPYING.LESSER and the latter was renamed to LICENSE to make more apparent that the code is licensed under LGPLv2 or later. - Moved from appveyor and travis to Github Actions for continuous integration. ### [`v2.5.3`](https://togithub.com/PyCQA/astroid/blob/master/ChangeLog#Whats-New-in-astroid-253) [Compare Source](https://togithub.com/PyCQA/astroid/compare/astroid-2.5.2...astroid-2.5.3) ============================ Release Date: 2021-04-10 - Takes into account the fact that subscript inferring for a ClassDef may involve **class_getitem** method - Reworks the `collections` and `typing` brain so that pylint\`s acceptance tests are fine. Closes [PyCQA/pylint#​4206](https://togithub.com/PyCQA/pylint/issues/4206) - Use `inference_tip` for `typing.TypedDict` brain. - Fix mro for classes that inherit from typing.Generic - Add inference tip for typing.Generic and typing.Annotated with `__class_getitem__` Closes [PyCQA/pylint#​2822](https://togithub.com/PyCQA/pylint/issues/2822)

---

Configuration

:date: Schedule: "every weekend" (UTC).

:vertical_traffic_light: Automerge: Disabled by config. Please merge this manually once you are satisfied.

:recycle: Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

:no_bell: Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box.

---

This PR has been generated by WhiteSource Renovate. View repository job log here.