Update edition to 2021

- Remove TryFrom/Into and FromIterator imports
- Prevent impl_validator_using_provider macro in sasl crate from
  constructing trait object

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

parsers/src/pubsub/event.rs

@@ -12,7 +12,6 @@ use crate::pubsub::{Item as PubSubItem, ItemId, NodeName, Subscription, Subscrip
 use crate::util::error::Error;
 use crate::Element;
 use jid::Jid;
-use std::convert::TryFrom;
 
 /// Event wrapper for a PubSub `<item/>`.
 #[derive(Debug, Clone)]

parsers/src/pubsub/owner.rs

@@ -12,7 +12,6 @@ use crate::pubsub::{AffiliationAttribute, NodeName, Subscription};
 use crate::util::error::Error;
 use crate::Element;
 use jid::Jid;
-use std::convert::TryFrom;
 
 generate_element!(
     /// A list of affiliations you have on a service, or on a node.

parsers/src/pubsub/pubsub.rs

@@ -13,7 +13,6 @@ use crate::pubsub::{
 use crate::util::error::Error;
 use crate::Element;
 use jid::Jid;
-use std::convert::TryFrom;
 
 // TODO: a better solution would be to split this into a query and a result elements, like for
 // XEP-0030.