Nextflow lint results

⚠️ Warnings

Warning: subworkflows/local/utils_nfcore_references_pipeline/main.nf:168:5: Emit name should be omitted when there is only one emit
```
    references = references
    ^^^^^^^^^^^^^^^^^^^^^
```

Warning: subworkflows/local/utils_references/main.nf:28:5: Variable was declared but not used

    references_file = get_references_file(references, param_file, attribute_file)
    ^^^^^^^^^^^^^^^

Warning: subworkflows/local/utils_references/main.nf:29:5: Variable was declared but not used

    references_value = get_references_value(references, param_value, attribute_value)
    ^^^^^^^^^^^^^^^^

Warning: workflows/references.nf:101:5: Emit name should be omitted when there is only one emit
```
    references = references // channel: [meta, *]
    ^^^^^^^^^^^^^^^^^^^^^
```