[BUG] process.env - Cannot read properties of undefined (reading 'env')

**Describe the bug**
Using `process.env.whatever` in a danger file leads to a runtime error stating that `process` is undefined.

**To Reproduce**
1. Create a dangerfile
2. Add a reference to `process.env`
3. See the error

**Expected behavior**
You should be able to access `process.env`

**Screenshots**

**Your Environment**

| software | version
| ---------------- | -------
| danger.js | 11.2.0
| node | `node:16` docker image
| npm | 7.11.0 (pnpm)
| Operating System | Gitlab CI

**Additional context**
Add any other context about the problem here.

Reproduce the issue with a dangerfile that references process.env under the reported Node 16 GitLab CI environment. Trace how dangerfiles are executed and verify that a dangerfile can read process.env without the runtime error; confirm the behavior in a focused test if the project has coverage for this execution path.

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