Chack whether `--assembly_type` parameter is requiered in nextflow run and update `README.md`

[Daniel-VM]

Description of the bug

The pipeline usage documentation might need to be updated because there seems to be an issue in the nextflow run command when the --assembly_type parameter is absent.

nextflow run nf-core/bacass \
  -profile <docker/singularity/.../institute> \
  --input samplesheet.tsv \
  --outdir <OUTDIR>

The issue aim is to check that the --assembly_type parameter is indeed required to run nf-core/bacass.

Command used and terminal output

No response

Relevant files

No response

System information

No response