Upgrade to actions/checkout@v4

[janivo]

Description

To resolve the node deprecation warning caused by the lower version of actions/checkout, we need to upgrade to version 4 of the actions/checkout action. This action is utilized in our GitHub Actions workflows to checkout the repository code. While version 4 is already implemented in our test.yml workflow, it needs to be applied consistently across all relevant workflows to mitigate the deprecation warning.

Acceptance Criteria

• Upgrade the actions/checkout action to version 4 in all GitHub Actions workflows where it is used.
• Verify that the node deprecation warning no longer occurs after upgrading to version 4.