permissions grantedTo should be a single identitySet

[butonic]

we should have used grantedToIdentities, which is a collection
https://learn.microsoft.com/en-us/graph/api/resources/permission?view=graph-rest-1.0

Since this is a breaking change we should

1. add the grantedToIdentitiesV2 collection
2. make all clients use that instead of grantedTo
3. correct grantedTo

grantedToIdentities and grantedTo have been marked as deprecated in msgraph ... in favor of grantedToV2 and grantedToIdentitiesV2, which use a SharePointIdentitySet instead of an IdentitySet. The biggest difference is that the sharePointIdentitySet also carries a group property to allow associating groups with actions.

[micbar]

Quick Fix:

• Rename grantedTo into grantedToIdentities.

@fschade will take care

[micbar]

Fixed by #74