zvariant-2.2.0

• GVariant format serialization and deserialization.
• Use and re-export zvariant_derive crate.
• Implement Type for Option<T: Type>. Note: This type is GVariant-only (at least at the moment).
  • Also provided in a Maybe type for Option<T> in a Value.
• Add generic wrapper types, SerializeValue and DeserializeValue, that serialize or deserialize the wrapped type as a Variant (i-e Value) type.
• Add OwnedSignature and OwnedObjectPath, Similar to what was done for OwnedValue, this is an owned version of Signature and ObjectPath.
• Add Signature::into_owned and ObjectPath::into_owned methods.
• DeserializeDict now skips unknown fields in serialized data.
• Put zvariant into the prelude instead of bringing it into scope where ever the derives are used.
• Implement From<String> for Value.
• Provide constants for Variant type signature.
• Other internal/minor changes.