Change our date format to be  [XMLSCHEMA11-2] 

Change our date format to be  [XMLSCHEMA11-2]  for VC 1.1 and 2.0

<img width="557" alt="image" src="https://github.com/TBD54566975/ssi-sdk/assets/5314059/a11c2cc6-a523-4986-8368-c103c6fcb1c4">

<img width="833" alt="image" src="https://github.com/TBD54566975/ssi-sdk/assets/5314059/61e5c3bc-4903-417e-9e78-9d92cfd55fcd">

Are we going to be backwards compatible with 1.0 when parsing dates?