You can define environment variables for the entire workflow by using the env key at the top level of the workflow file. These environment variables will be available to all jobs and steps within the workflow.
Environment variables can also be set within the run attribute of a job step, and these variables will be scoped only to that specific step.
You can set environment variables for specific steps within a job by using jobs..steps[*].env, which allows you to define variables that will only be available to that step.
