clinvar-gk-pilot to use vrs-python w/ dependency on hgvs lib from 225-uncertain-ranges branch

[toneillbroad]

Larry wanted me to generate some gk-pilot data files using changes currently on the vrs-python issue-360 branch to get the mitochondrial changes in the “Add support for mito m. in translate_from” PR and the hgvs 225-uncertain-ranges branch to get the changes in the “Uncertain Ranges” PR. I did that locally on my machine, but now Larry would like to run the code on his machine.

This will require:

1. pushing these changes into vrs-python,
2. pre-release tagging that PR merge,
3. and updating clinvar-gk-python to refer to vrs-python dependency with the new pre-release tag.

[toneillbroad]

Kori wants to be sure that Alex reviews the PR before merging (step 1 above)
Once merged and tagged, I can move forward with #'s 2 and 3.