feat: subtext under pr title

src/api/graphql/fetch_pull_request.graphql

@@ -6,6 +6,17 @@ query PullRequestQuery($id: ID!) {
             body
             state
             isDraft
+            baseRef {
+                name
+            }
+            headRef {
+                name
+            }
+            author {
+                __typename
+                login
+                avatarUrl(size: 32)
+            }
         }
     }
 }