Replace qiskit-terra dev requirement with qiskit

[coruscating]

Summary

Now that the metapackage has been removed in Qiskit/qiskit#11271, we should be able to run the daily cron jobs against qiskit and not qiskit-terra.

[wshanks]

Can't we go ahead an revert #1323, meaning removing the qiskit_pkg lines from tox.ini and changing the dependency in requirements.txt back to qiskit from qiskit-terra?

[wshanks]

Sorry, I got mixed up about which things had been reverted or not. This looks good!

[wshanks]

Actually, one question (I will try to check but posting here before this merges) -- why do we have qiskit>=0.44 in requirements.txt and qiskit>=0.45 in requirements-dev.txt?

[wshanks]

I looked up the 0.44 vs 0.45 issue. It is because 0.45 introduced singleton gates and (I think) the iqp drawing style for circuits both of which the docs build needs.

[wshanks]

By the way, I was curious why the cron run from last night didn't fail. Because of the way we reverted things, we were specifying qiskit>=0.44, qiskit-terra>=0.45 and git+https://github.com/Qiskit/qiskit. With the dropping of the metapackage, these requirements can be installed. If we had been installing qiskit_pkg, there would have been an error. These requirements are ambiguous. They install qiskit-terra and the new qiskit from the repo which both install files into qiskit in site-packages. One of them probably clobbers the other, so we might have actually been testing against terra 0.45 instead of qiskit main, but this PR will remove that ambiguity.

[coruscating]

Ahh, that makes sense. We definitely were testing against Qiskit 0.45 because the rendered circuits are in the new iqp style. We actually could have stuck with using 0.44 for docs builds, but the circuits would have been drawn in the old style (though it looks like the Qiskit docs haven't switched over to the new style either).