Drop python 3.7 support

[t-imamichi]

Summary

Qiskit has dropped support Python 3.7 and this follows suit for Qiskit Optimization.
follows qiskit-community/qiskit-finance#288

depends on #536

Details and comments

[woodsp-ibm]

pyproject.toml and tox.ini both have py37 entries that should be removed too

[coveralls]

Pull Request Test Coverage Report for Build 5940174572

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 92.416%

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Totals
Change from base Build 5932990441:	0.0%
Covered Lines:	4448
Relevant Lines:	4813

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💛 - Coveralls

[t-imamichi]

@woodsp-ibm I guess we need to configure somewhere to update the following entries to Python 3.8. Do you have any ideas? We can update the configuration after merging this PR.

[woodsp-ibm]

I guess we need to configure somewhere to update the following entries to Python 3.8. Do you have any ideas? We can update the configuration after merging this PR.

@t-imamichi They are edited under the Settings for the repo - select Branches from the left and you will see Branch Protection Rules and you can Edit the rules for the main branch. Should probably make sure the new 3.11 tutorials is required too. Once you edit the rules the checks here should alter accordingly. (I think all the checks listed we have as required normally - except the Summary one mergify puts in there).

Don't forget also the comment above about the two other files that should be updated - i.e the removal of py37 in them now that this drops 3.7 support etc.

[t-imamichi]

Thanks. I succeeded in updating the configuration.

[woodsp-ibm]

Looks good, just missing these two file being updated to remove py37 envs

qiskit-optimization/tox.ini

Line 3 in 3f21208

envlist = py37, py38, py39, py310, py311, lint

qiskit-optimization/pyproject.toml

Line 7 in 3f21208

target-version = ['py37', 'py38', 'py39', 'py310']

And I note in the latter (pyproject.toml) we forgot to add py311 to that list for black so maybe that can be added, and we can fix it here, while removing the py37

[t-imamichi]

Thanks. I updated tox.ini and pyproject.toml.

[woodsp-ibm]

LGTM