Only valid as a `type` for a `CommandLineTool` output with no
`outputBinding` set.

The following

```
outputs:
  an_output_name:
  type: stderr

stderr: a_stderr_file
```

is equivalent to

```
outputs:
  an_output_name:
    type: File
    streamable: true
    outputBinding:
      glob: a_stderr_file

stderr: a_stderr_file
```

If there is no `stderr` name provided, a random filename will be created.
For example, the following

```
outputs:
  an_output_name:
    type: stderr
```

is equivalent to

```
outputs:
  an_output_name:
    type: File
    streamable: true
    outputBinding:
      glob: random_stderr_filenameABCDEFG

stderr: random_stderr_filenameABCDEFG
```
