Function is_ci 

pub fn is_ci() -> bool

Check if the current process is running in a CI environment.

This checks for common CI environment variables used by popular CI/CD systems:

• CI - Generic CI indicator (GitHub Actions, GitLab CI, CircleCI, Travis CI, etc.)
• GITHUB_ACTIONS - GitHub Actions
• GITLAB_CI - GitLab CI
• BUILDKITE - Buildkite
• JENKINS_URL - Jenkins
• CIRCLECI - CircleCI
• TRAVIS - Travis CI
• BITBUCKET_PIPELINES - Bitbucket Pipelines
• AZURE_PIPELINES - Azure Pipelines
• TF_BUILD - Azure DevOps / Team Foundation Build
• DRONE - Drone CI
• TEAMCITY_VERSION - TeamCity

Returns true if any of these environment variables are set to a truthy value.