Parsing npm outdated output with multiple dependents per dependency fails

[fniessink]

Parse error
Traceback (most recent call last):
  File "/home/collector/base_collectors/source_collector.py", line 150, in __safely_parse_source_responses
    return await self._parse_source_responses(responses)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/collector/base_collectors/source_collector.py", line 163, in _parse_source_responses
    included_entities = [entity for entity in await self._parse_entities(responses) if self._include_entity(entity)]
                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/collector/base_collectors/file_source_collector.py", line 113, in _parse_entities
    entities.extend(self._parse_json(json, filename))
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/collector/source_collectors/npm/dependencies.py", line 15, in _parse_json
    return Entities(
           ^^^^^^^^^
  File "/home/collector/model/entity.py", line 34, in __init__
    self.extend(entities)
  File "/home/collector/model/entity.py", line 52, in extend
    for entity in entities:
  File "/home/collector/source_collectors/npm/dependencies.py", line 17, in <genexpr>
    key=<redacted>'{dependency}@{versions.get("current", "?")}',
                        ^^^^^^^^^^^^
AttributeError: 'list' object has no attribute 'get'

{
"@testing-library/jest-dom": [
    {
      "current": "6.4.6",
      "wanted": "6.5.0",
      "latest": "6.5.0",
      "dependent": "foo",
      "location": "/builds/project/baz/node_modules/@testing-library/jest-dom"
    },
    {
      "current": "6.4.6",
      "wanted": "6.5.0",
      "latest": "6.5.0",
      "dependent": "bar",
      "location": "/builds/project/baznode_modules/@testing-library/jest-dom"
    }
  ]
}