Support subscriptions extensions [WIP]

[nrbnlulu]

Description

This is an initial implementation for subscription extensions.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Documentation

Issues Fixed or Closed by This PR

closes #2097

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[botberry]

Thanks for adding the RELEASE.md file!

Here's a preview of the changelog:

---

Initial schema-extensions support for subscriptions operations.
i.e:

def on_execute(self):
    #  This part is called before the async-generator yields
    yield
    #  This part is called after the async-generator yields

Note that the resolve hook is not yet supported due to lack of support from graphql-core.

---

Here's the preview release card for twitter:

Here's the tweet text:

🆕 Release (next) is out! Thanks to ניר for the PR 👏

Get it here 👉 https://github.com/strawberry-graphql/strawberry/releases/tag/(next)

[botberry]

Hi, thanks for contributing to Strawberry 🍓!

We noticed that this PR is missing a RELEASE.md file. We use that to automatically do releases here on GitHub and, most importantly, to PyPI!

So as soon as this PR is merged, a release will be made 🚀.

Here's an example of RELEASE.md:

Release type: patch

Description of the changes, ideally with some examples, if adding a new feature.

Release type can be one of patch, minor or major. We use semver, so make sure to pick the appropriate type. If in doubt feel free to ask :)

Here's the tweet text:

🆕 Release (next) is out! Thanks to ניר for the PR 👏

Get it here 👉 https://github.com/strawberry-graphql/strawberry/releases/tag/(next)

[codecov]

Codecov Report

Merging #2810 (20bcfed) into main (b798287) will decrease coverage by 0.25%.
The diff coverage is 96.52%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2810      +/-   ##
==========================================
- Coverage   96.36%   96.12%   -0.25%     
==========================================
  Files         197      198       +1     
  Lines        8315     8405      +90     
  Branches     1520     1529       +9     
==========================================
+ Hits         8013     8079      +66     
- Misses        191      211      +20     
- Partials      111      115       +4