use collections.abc

[saraedum]

MutableMapping has been removed from collections in Python 3.10.

(this was deprecated since Python 3.3 apparently)

[saraedum]

We should probably also add 3.10 to the Python versions tested in test.yml. Maybe we should also bump the Python version 3.6 in test.yml since 3.6 is near end-of-life.

But these should probably go into a separate PR.

[saraedum]

Not sure whether the failing tests can have anything to do with what I've been doing here.

[eldipa]

Yes, the tests are failing not because of the PR but because I added a test a week ago that checks the version of byexample in the documentation, but it was designed to work in the developer's environment, not in CI/github.

Also, the tests for Golang are failing. I tracked the issue to a problem in upstream (in the interpreter of go).

I will review this PR today late but I think it perfect.

Thanks for the contribution!

[eldipa]

I ran the tests and everything worked perfect. Merging. I will cut a new release probably at the end of the week.

Thanks a lot!