Nextflow lint results

⚠️ Warnings

Warning: main.nf:54:5: Emit name should be omitted when there is only one emit

    multiqc_report = DEMO.out.multiqc_report // channel: /path/to/multiqc_report.html
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Warning: subworkflows/nf-core/utils_nextflow_pipeline/main.nf:43:5: Emit name should be omitted when there is only one emit
```
    dummy_emit = true
    ^^^^^^^^^^^^^^^
```
Warning: subworkflows/nf-core/utils_nfcore_pipeline/main.nf:16:5: Variable was declared but not used
```
    valid_config = checkConfigProvided()
    ^^^^^^^^^^^^
```
Warning: subworkflows/nf-core/utils_nfcore_pipeline/main.nf:20:5: Emit name should be omitted when there is only one emit
```
    valid_config
    ^^^^^^^^^^^^
```
Warning: subworkflows/nf-core/utils_nfschema_plugin/main.nf:72:5: Emit name should be omitted when there is only one emit
```
    dummy_emit = true
    ^^^^^^^^^^^^^^^
```