properly populate the EnvironmentVariable struct

[felixlut]

Checklist

=========

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have checked for similar issues and haven't found anything relevant.
• This is not a security issue (which should be reported here: https://circleci.com/security/)
• I have read Contribution Guidelines.

Internal Checklist

• I am requesting a review from my own team as well as the owning team
• I have a plan in place for the monitoring of the changes that I am making (this can include new monitors, logs to be aware of, etc...)

Changes

=======

• Properly populate the EnvironmentVariable struct with json tags
• Added updated_at while at it, as per the API docs.

Rationale

=========

Before this change, listing the environment variables in a context would result in each environment variable not being properly populated. The image below is the result of running fmt.Errorf("%+v\n", envVariable), where envVariable is an environmental variable extracted from a EnvironmentVariables() call. The only thing that gets populated is the name.

With the json tags, the same print produces:

Considerations

==============

It didn't work properly, now it does.

Screenshots

See screenshots above

Here are some helpful tips you can follow when submitting a pull request:

1. Fork the repository and create your branch from main.
2. Run make build in the repository root.
3. If you've fixed a bug or added code that should be tested, add tests!
4. Ensure the test suite passes (make test).
5. The --debug flag is often helpful for debugging HTTP client requests and responses.
6. Format your code with gofmt.
7. Make sure your code lints (make lint). Note: This requires Docker to run inside a local job.

[JulesFaucherre]

Thank you for this 🙏

[felixlut]

Hey! Is there anything else I should do? Or is this just pending a merge? The failed job is for some security thing, which my change shouldn't effect

[JulesFaucherre]

Hey, actually no, it only seems that you can't run this check because you're not part of the org, I merge the PR