Add upload_url as action output (#75)

* Add upload_url as action output

* Update README

src/main.ts

@@ -55,6 +55,7 @@ async function run() {
     }
     console.log(`🎉 Release ready at ${rel.html_url}`);
     setOutput("url", rel.html_url);
+    setOutput("upload_url", rel.upload_url);
   } catch (error) {
     setFailed(error.message);
   }