Suppress animation in CI contexts

[ben-edna]

When running in a CI context, animations give a lot of log output, but add no value.

Suppress the animation when an env var CI is defined as true or 1

• https://github.blog/changelog/2020-04-15-github-actions-sets-the-ci-environment-variable-to-true/
• Jenkins defines CI
• https://docs.gitlab.com/ci/variables/predefined_variables/
• https://circleci.com/docs/variables/