Work on Jest AE v4 with Jest 27 support

[IlCallo]

After we released at least the beta for Jest AE v3, we should create v4 alpha version with Jest 27 support, which has much more breaking changes

I'm still unsure on how to manage this, as we need to maintain both versions for a while, eg. until Qv3 comes out

I guess we could just duplicate the Jest folder and call the v3 one unit-jest-v3, but this would then prevent us from testing Jest AE v3 and v4 together into test-projects, or force us to create more and more test-projects to test multiple AE versions

Or we could follow the lead of vue-jest and just release different packages to support different Jest versions
I'd like to avoid the latter as it increases the project complexity and we'll end up using different test-projects anyway due to conflicting Jest configurations

[estrom85]

We are now having some security issues with Jest 26 on our project.

What is the status with adding support for Jest 27 or higher? When can we expect to have the support available?

Thanks.

[IlCallo]

Closing as we'll support Jest up to 29 directly into v3 beta release
#241 (comment)