Bump actions/checkout and actions/setup-python actions to latest major

[magnetikonline]

What does this PR do?

Bumping actions/checkout and actions/setup-python actions to their latest major versions.

These both now support Node.js v16 - which is installed on GitHub Action cloud runners as v14 starts to fade away....

Motivation

Quality of life update

Testing Guidelines

Ran workflows.

Additional Notes

N/A

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR passes the integration tests (ask a Datadog member to run the tests)
• This PR passes the unit tests
• This PR passes the installation tests (ask a Datadog member to run the tests)

[magnetikonline]

ping @jvanbrie / @IvanTopolcic

[magnetikonline]

ping @tianchu

[magnetikonline]

hey @astuyve are you able to look at this?

[astuyve]

Thanks for the PR @magnetikonline! Sorry for the delay

[magnetikonline]

Not a problem @astuyve, happy to contribute 👍