Use SINTEF/ci-cd v2.1.0 in CI/CD workflows

[CasperWA]

Description:

Fixes #545

The usage of v2.1.0 for the SINTEF/ci-cd utility repository should result in prioritizing the usage of the supplied PAT secret, i.e., a custom personal access token instead of the generic GITHUB_TOKEN, which has some harsh rate-limits for GH API requests.

Type of change:

• Bug fix.
• New feature.
• Documentation update.

Checklist:

This checklist can be used as a help for the reviewer.

• Is the code easy to read and understand?
• Are comments for humans to read, not computers to disregard?
• Does a new feature has an accompanying new test (in the CI or unit testing schemes)?
• Has the documentation been updated as necessary?
• Does this close the issue?
• Is the change limited to the issue?
• Are errors handled for all outcomes?
• Does the new feature provide new restrictions on dependencies, and if so is this documented?

Comments: