[fix] Avoid default_app_config Deprecation Warning in Django >= 3.2

[bluppfisk]

This will stop Django 3.2 and higher from raising Deprecation Warnings because default_app_config is no longer necessary and will be removed in 4.1. Note that it breaks backward incompatibility with Django < 3.2 so it should only be used in releases dropping <3.2 support.

Yes, It may be a bit early for this one :)

[bluppfisk]

done :)

[auvipy]

please check the build failures

[auvipy]

• missing prefix in the commit short description Eg: "[feature/fix/change] Action performed"

Please read our guidelines at: http://openwisp.io/docs/developer/contributing.html#commit-message-style-guidelines ERROR: Commit message check failed! Checked commit message:

[bluppfisk]

ok tried my best :)

[auvipy]

I had to fixed a merge conflict, can you please pull & run flake8 check and push again?

[auvipy]

Your commit message does not follow our commit message style guidelines:

• please add a capital letter after the prefix

Please read our guidelines at: http://openwisp.io/docs/developer/contributing.html#commit-message-style-guidelines Checked commit message:

[fix] flake8 formatting ERROR: Commit message check failed!

[auvipy]

strange, it was green in the PR & showing failure after merge!

[bluppfisk]

Not sure why. The QA checks seem very strict for this project. Not necessarily a bad thing, but it looks like it thinks I've mentioned a particular issue (I didn't) and is angry at me for not mentioning that it is fixed in this PR. At least the code should work fine.

[nemesifier]

The problem was fixed in #270 and it was not a strictly QA check issue as far as I understood. @bluppfisk QA checks enforce consistency, we do this across all openwisp modules and it helps maintainers like me to maintain a lot of different packages faster because I can find things more easily.

[batisteo]

Would it be possible to have a minor release with this fix? :pray: