Upgrade CI workflow actions

[merc1er]

Upgrade actions/checkout@v2 to actions/checkout@v3 and so on.

test (3.9)
The following actions uses node12 which is deprecated and will be forced to run on node16: actions/checkout@v2, actions/setup-python@v2, codecov/codecov-action@v1. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/

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