Change the aiida-core version to 2.0 for qe workchain lib

[unkcpz]

I have to push this change to the qe-workchain and make a tagged release for future use.
It seems a bit weird but if we don't want to break the current release strategy for aiidalab-qe-workchain, this is a have to change from my perspective.
The plan is

1. first get this merged to the master and make a tagged release 22.11.2a0,
2. then I'll revert the change for master branch to make the impact limited.
3. The test is based on pytest-docker which implemented in Mig/2.1 #271 can then continued by tagging the aiidalab-qe-workchain to 22.11.2a0.

[unkcpz]

Hi @superstar54, I recheck this issue the next day with a clear head, and found it is a stupid implementation 😆
I am now using requirements_test.txt for installing test dependencies and embedding the file inside the setup.cfg as suggested in https://setuptools.pypa.io/en/latest/userguide/declarative_config.html#options.