rss: Add crates namespace

Author: Turbo87

src/tests/worker/rss/snapshots/all__worker__rss__sync_updates_feed__sync_updates_feed-2.snap

@@ -3,7 +3,7 @@ source: src/tests/worker/rss/sync_updates_feed.rs
 expression: content
 ---
 <?xml version="1.0" encoding="utf-8"?>
-<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
+<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:crates="https://crates.io/">
     <channel>
         <title>crates.io: recent updates</title>
         <link>https://crates.io/</link>

src/worker/jobs/rss/sync_updates_feed.rs

@@ -39,12 +39,16 @@ impl BackgroundJob for SyncUpdatesFeed {
             .map(|u| u.into_rss_item(domain))
             .collect();
 
+        let namespaces = vec![("crates".to_string(), "https://crates.io/".to_string())];
+        let namespaces = namespaces.into_iter().collect();
+
         let channel = rss::Channel {
             title: "crates.io: recent updates".to_string(),
             link: format!("https://{domain}/"),
             description: "Recent version publishes on the crates.io package registry".to_string(),
             language: Some("en".to_string()),
             atom_ext: Some(rss::extension::atom::AtomExtension { links: vec![link] }),
+            namespaces,
             items,
             ..Default::default()
         };