Issuer name optional in spec, mandatory in schema

[nklomp]

According to the text at https://identity.foundation/credential-manifest/#general-composition :

The object MUST contain an issuer property, and its value MUST be an object composed as follows: The object MUST contain a id property, and its value MUST be a valid URI string that identifies who the issuer of the credential(s) will be. The object MAY contain a name property, and its value MUST be a string that SHOULD reflect the human-readable name the Issuer wishes to be recognized by.

According the the schema:

 "issuer": {
      "type": "object",
      "required": [
        "id",
        "name"
      ],
      "properties": {
        "id": {
          "type": "string"
        },
        "name": {
          "type": "string"
        },
        "styles": {
          "$ref": "https://identity.foundation/wallet-rendering/schemas/entity-styles.json"
        }
      },
      "additionalProperties": false
    }

I think it makes sense to have the name required. Although it is self asserted by the issuer, it is the only human friendly reference for a holder.

[nklomp]

Consensus in the meeting seemed to be to make the name optional in the schema, so PR removes the required flag