fix: CLIN-3610 use container tag 1.20 instead latest for split multia…

[LysianeBouchard]

We are currently using the "latest" tag for the bcftools container in the SplitMultiAllelics process.

To make the pipeline more stable and reproducible, we will use a specific tag instead (1.20). We used the same version as other processes based on bcftools.

Tests

Run the pipeline locally on this branch and on the main branch:
nextflow run main.nf -profile test,docker

Compare the output for the splitMultiAllelics process. The bodies of the vcf files should be identical.

On the current branch, open the nextflow execution report (pipeline info output folder) and double check that the container is bcftools:1.20

Juno tests

Run the pipeline in juno. Make sure that the container used if bcftools:1.20 and not bcftools:latest.

Linter Warnings

For the linter, we still see the warning Container versions do not match for the split_multi_allelics module, which is also present on the main branch. We thought simply removing the container definition in the module would fix it, but it doesn't. We will not address this problem in the present PR. We shall revisit this later when standardizing the module.

PR checklist

• This comment contains a description of changes (with reason).
• If you've fixed a bug or added code that should be tested, add tests!
• If you've added a new tool - have you followed the pipeline conventions in the contribution docs
• Make sure your code lints (nf-core lint).
• Ensure the test suite passes (nextflow run . -profile test,docker --outdir <OUTDIR>).
• Check for unexpected warnings in debug mode (nextflow run . -profile debug,test,docker --outdir <OUTDIR>).
• Usage Documentation in docs/usage.md is updated.
• Output Documentation in docs/output.md is updated.
• Reference Data Documentation in docs/reference_data.md is updated.
• CHANGELOG.md is updated.
• README.md is updated (including new tool citations and authors/contributors).