urlencode label name when deleting

Spaces are legal in label names, but get errors if they're not escaped.
This feels like a responsibility of the thing constructing URLs, but I
can understand if it should actually be the caller's responsibility.

Author: illicitonion

src/api/issues.rs

@@ -480,7 +480,7 @@ impl IssueHandler<'_> {
     /// # }
     /// ```
     pub async fn delete_label(&self, name: impl AsRef<str>) -> Result<()> {
-        let route = format!("/{}/labels/{name}", self.repo, name = name.as_ref(),);
+        let route = format!("/{}/labels/{name}", self.repo, name = utf8_percent_encode(name.as_ref(), NON_ALPHANUMERIC));
 
         self.crab._delete(route, None::<&()>).await?;
         Ok(())