Set the dns_resolution feature in OMDomainResolver

`OMDomainResolver` actually does support building DNSSECProofs, so
should be setting the `dns_resolution` `NodeFeature` flag.

Author: TheBlueMatt

lightning-dns-resolver/Cargo.toml

@@ -9,6 +9,7 @@ edition = "2021"
 
 [dependencies]
 lightning = { version = "0.0.124", path = "../lightning", default-features = false }
+lightning-types = { version = "0.1", path = "../lightning-types", default-features = false }
 dnssec-prover = { version = "0.6", default-features = false, features = [ "std", "tokio" ] }
 tokio = { version = "1.0", default-features = false, features = ["rt"] }
 

lightning-dns-resolver/src/lib.rs

@@ -21,6 +21,8 @@ use lightning::onion_message::messenger::{
 	MessageSendInstructions, Responder, ResponseInstruction,
 };
 
+use lightning_types::features::NodeFeatures;
+
 use tokio::runtime::Handle;
 
 #[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
@@ -126,6 +128,12 @@ where
 		None
 	}
 
+	fn provided_node_features(&self) -> NodeFeatures {
+		let mut features = NodeFeatures::empty();
+		features.set_dns_resolution_optional();
+		features
+	}
+
 	fn release_pending_messages(&self) -> Vec<(DNSResolverMessage, MessageSendInstructions)> {
 		core::mem::take(&mut *self.state.pending_replies.lock().unwrap())
 	}