Add temporary asgiref requirement

[ddabble]

Description

#1209 added an implicit dependency on asgiref>=3.6, as the imported function iscoroutinefunction() was introduced in asgiref 3.6.0 (see asgiref's changelog), but a lower version is the minimum requirement of Django 4.1 and earlier (see e.g. Django 4.1.11's setup.cfg).

This means that users who happen to install django-simple-history together with Django 4.1 or lower, might implicitly also install a lower version of asgiref than what's actually required to run our code.

The easiest solution to this seems to be adding a requirement for asgiref>=3.6, which can be removed when our minimum required Django version is 4.2 or higher.

Related Issue

Closes #1255.

Motivation and Context

See the discussion of the issue linked above.

How Has This Been Tested?

Through GitHub actions.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  • This seems unlikely, however, as I'm assuming that most users of this library simply rely on the same version of asgiref as is installed with the Django version they're using

Checklist:

• I have run the pre-commit run command to format and lint.
• 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 added my name and/or github handle to AUTHORS.rst
• I have added my change to CHANGES.rst
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #1261 (d1ce47a) into master (329659b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1261   +/-   ##
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  Coverage   96.94%   96.94%           
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  Files          23       23           
  Lines        1277     1277           
  Branches      210      210           
=======================================
  Hits         1238     1238           
  Misses         21       21           
  Partials       18       18           

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[amandeep-r]

Would it be possible to get a release out including this change?

[ddabble]

Sure, working on a release PR (#1290) right now 🙂