Support extensions for subscriptions

[nrbnlulu]

Description

Support extensions for subscriptions.

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

This PR follows #2428

Notes:

• resolve Is not supported due to lack of support in graphql-core
  see this issue

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).

[codecov]

Codecov Report

Merging #2430 (16015df) into main (3430d85) will increase coverage by 0.02%.
The diff coverage is 99.16%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2430      +/-   ##
==========================================
+ Coverage   96.30%   96.33%   +0.02%     
==========================================
  Files         184      184              
  Lines        7571     7714     +143     
  Branches     1394     1409      +15     
==========================================
+ Hits         7291     7431     +140     
- Misses        179      181       +2     
- Partials      101      102       +1     

[botberry]

Thanks for adding the RELEASE.md file!

Here's a preview of the changelog:

---

Support Extensions on subscriptions
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

---

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)

[patrick91]

@nrbnlulu would you have time to update this PR? :D