static mandatory string component should go outside CWL Parameter References

[mr-c]

glob: $(inputs.outputVcf).tbi is better than glob: $(inputs.outputVcf + ".tbi")

Many CWL runners (including cwltool) will be able to parse the first way without calling out to a Javascript engine

[mr-c]

This might not be worth doing here, as it is cleaner to match the structure of the source WDL for string interpolation. Lets keep this for post-processing in cwl-format