Values for acr_values_supported in Metadata Policy of a TA to an OP

[abisegna]

The current policy metadata of a TA to an OP in acr_values_supported refers that an OP that supports SpidL1 and SpidL2 would fail because the policy requires the OP to support SpidL1, SpidL2 and SpidL3.

Please evaluate whether changes are appropriate based on the following:

• superset_of is an array which MUST contain https://www.spid.gov.it/SpidL1, https://www.spid.gov.it/SpidL2
• subset_of is an array which MUST contain https://www.spid.gov.it/SpidL1, https://www.spid.gov.it/SpidL2, https://www.spid.gov.it/SpidL3