feat: fetch data for prs that need retest

src/lib/get_pull.mjs

@@ -0,0 +1,11 @@
+export default async function getPull(repo, id) {
+  const pull = await repo.pulls(id).fetch();
+  return {
+    id: pull.id,
+    url: pull.url,
+    number: pull.number,
+    state: pull.state,
+    title: pull.title,
+    labels: pull.labels.map(label => label.name),
+  };
+}