Contamination file extension

[yashpatel6]

    @yashpatel6 Minor point but it looks like this is just a TSV file and if so, we probably want to consider using `.tsv` instead to limit the number of extensions to use although I know [the developer's documentation](https://gatk.broadinstitute.org/hc/en-us/articles/360036888972-CalculateContamination) uses `.table`

Originally posted by @tyamaguchi-ucla in uclahs-cds/pipeline-call-sSNV#129 (comment)