Add option to use --scaled for sourmash

[olgabot]

Addresses https://github.com/nf-core/kmermaid/issues/78

PR checklist

• [x] PR is to dev rather than master
• [x] This comment contains a description of changes (with reason)
• [x] If you've fixed a bug or added code that should be tested, add tests!
• [x] Ensure the test suite passes (nextflow run . -profile test,docker).
• [x] Make sure your code lints (nf-core lint .).
• [x] Documentation in docs is updated
• [x] CHANGELOG.md is updated
• [x] README.md is updated

[olgabot]

related: https://github.com/ewels/MultiQC/issues/986

[pranathivemuri]

test_ska needs one of the sketch size parameters mentioned otherwise it results in this error - None of --sketch_size, --sketch_size_log2, --sketch_scaled, --sketch_scaled_log2 was provided! Provide one (1) and only one to specify the style and amount of hashes per sketch 2 other errors

Channel csv has been used twice as an output by process sourmash_compute_sketch_fastx_peptide and process sourmash_compute_sketch_fastx_nucleotide

[77/7d6366] Submitted process > validate_sketch_values ERROR ~ No signature of method: groovyx.gpars.dataflow.DataflowQueue.branch() is applicable for argument types: (_nf_script_be9e5bac$_run_closure66) values: [_nf_script_be9e5bac$_run_closure66@75f2099] Possible solutions: each(groovy.lang.Closure), any(), print(), mean(), bind(java.lang.Object), any(groovy.lang.Closure) -- Check script 'main.nf' at line: 897 or see '.nextflow.log' file for more details

[pranathivemuri]

want to resolve conflicts, fix tests, and merge into dev? the code generally looks good once you have addressed the comments.

[olgabot]

want to resolve conflicts, fix tests, and merge into dev? the code generally looks good once you have addressed the comments.

Yep thanks! I'll take care of the conflicts.