Make URL optional for AUR queries

src/commands/aur.rs

@@ -42,7 +42,7 @@ struct Package {
     #[serde(rename = "Description")]
     description: String,
     #[serde(rename = "URL")]
-    url: String,
+    url: Option<String>,
     #[serde(rename = "NumVotes")]
     votes: u16,
     #[serde(rename = "Popularity")]
@@ -54,7 +54,11 @@ impl fmt::Display for Package {
         write!(
             f,
             "aur/{} {} (+{})\n    {}\n    url: {}",
-            self.name, self.version, self.votes, self.description, self.url
+            self.name,
+            self.version,
+            self.votes,
+            self.description,
+            self.url.clone().unwrap_or(String::from("none"))
         )
     }
 }