Update with native EL8/EL9 instructions

[nsmith-]

No description provided.

[nsmith-]

Arguably we should checkout a specific combine version, e.g.

cd HiggsAnalysis/CombinedLimit
git co v9.2.1
cd ../..

[nsmith-]

We could start minting releases and actually pushing to pypi rather than installing from git. @rkansal47 thoughts?

[rkansal47]

@nsmith- I agree. Actually I think we already started doing that :) https://pypi.org/project/rhalphalib, but there just haven't been any major updates since then (until now).

[rkansal47]

Wow this is working with CMSSW_14_1_0_pre4 now with your fixes from #42?? 🎉

[nsmith-]

Ok, can you approve & merge this? I'll work on making sure the release pipeline still works

[nsmith-]

yeah specifically 456e903 was what seemed to be breaking newer ROOT versions.

[rkansal47]

Yes, testing now on an el8 machine.

[rkansal47]

Worked perfectly on el8, thanks! Finally, we can stop using el7 containers...

[rkansal47]

Oof why is the test failing now?

[nsmith-]

The conda install seems to be a bit flaky

[nsmith-]

Looks like this is a well-known thing and hopefully will be fixed soon: conda-incubator/setup-miniconda#392
For now I guess I'll re-run