Plan out version migration for old/new XML model

[theferrit32]

• Create a final v1_1_0 release which will parse the old ClinVar XML
• Re-run prior releases which used older code versions, using the new v1_1_0 pipeline, so that they are all tagged as v1_1_0 and all the parsing logic is the same.
• Create a tag/branch for v2_x

[theferrit32]

@toneillbroad created a v1_1_0 tag. https://github.com/clingen-data-model/clinvar-ingest/releases/tag/v1_1_0

Any future changes to ClinVar v1 models will need to be created on a branch starting from v1_1_0.

ClinVar v2/new/somatic changes are all in main now.

Prior releases before v2 may be left as-is. If they need to be re-run we will do that in a separate ticket.