diff --git a/lib/datasource/github.js b/lib/datasource/github.js
index 65f89bfdadfd65b61aff984c4334b8fc1e692160..d69b26765cd4b0598ca479b35b2cb1c21a12b7fd 100644
--- a/lib/datasource/github.js
+++ b/lib/datasource/github.js
@@ -9,7 +9,6 @@ module.exports = {
 
 async function getDependency(repo, options = {}) {
   const ref = options.ref || 'tag';
-  const clean = options.clean === 'true';
   let versions;
   let endpoint;
   let token;
@@ -51,7 +50,7 @@ async function getDependency(repo, options = {}) {
     return null;
   }
   versions = versions.filter(version => isVersion(version));
-  if (clean) {
+  if (options.clean === 'true') {
     versions = versions.map(version => version.replace(/^v/, ''));
   }
   const dependency = {