manager: Remove Stale label if present

The stale label provides an easy way to force CI runs for issues after
changing dependencies.

techtree-manager/src/issue.rs

@@ -78,5 +78,42 @@ pub async fn update_bot_comment(
         )
         .await
         .context("Failed to update comment body")?;
+
+    Ok(())
+}
+
+pub async fn remove_stale_label(
+    forgejo: &forgejo_api::Forgejo,
+    meta: &crate::event_meta::RepoMeta,
+    issue_number: u64,
+) -> anyhow::Result<()> {
+    let labels = forgejo
+        .issue_get_labels(&meta.owner, &meta.name, issue_number)
+        .await
+        .context("Failed fetching issue labels")?;
+
+    let stale_label_id = labels
+        .iter()
+        .filter(|l| l.name.as_deref() == Some("Stale"))
+        .next()
+        .map(|l| l.id.unwrap());
+
+    if let Some(stale_label_id) = stale_label_id {
+        log::info!("Removing `Stale` label from issue #{issue_number}...");
+
+        forgejo
+            .issue_remove_label(
+                &meta.owner,
+                &meta.name,
+                issue_number,
+                stale_label_id,
+                forgejo_api::structs::DeleteLabelsOption {
+                    updated_at: Some(time::OffsetDateTime::now_utc()),
+                },
+            )
+            .await
+            .context("Failed to remove the `Stale` label")?;
+    }
+
     Ok(())
 }