ENH: Upgrade GitHub actions to `checkout@v3` and `setup-python@v3`

[dyollb]

Fix Node.js warnings linked to GitHub actions: upgrade to actions/checkout@v3 and actions/setup-python@v3.

Fixes:

cov / build (3.9, ubuntu-latest, pip)
Node.js 12 actions are deprecated.
For more information see:
https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/.
Please update the following actions to use Node.js 16:
actions/checkout@v2, actions/setup-python@v2

raised for example in: https://github.com/InsightSoftwareConsortium/ITKModuleTemplate/actions/runs/3594726041

Fixes issue #141 (replaces #144)

[jhlegarreta]

The commit does not have a body, i.e. what does the commit do?

(commit subject; capitalize first letter after the colon)

Upgrade to actions/checkout@v3 in GitHub Actions CI workflows.

Fixes: (triple backtick) Node.js 12 actions are deprecated. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/. Please update the following actions to use Node.js 16: actions/checkout (triple backtick)

(or whatever the exact warning is)

raised for example in: (please point here to the CI build line that shows the error; e.g. https://github.com/InsightSoftwareConsortium/ITKModuleTemplate/actions/runs/3593781857/jobs/6051189999#step:2:158 I have not been able to find the exact line)

Thanks for the patience @dyollb. Accurate commit messages help a lot when finding out why a change was introduced.

[jhlegarreta]

Push-forced. Upgraded Python setup actions as well.

[dzenanz]

Thank you @dyollb and @jhlegarreta.