Use a clean prefix when deploying

lib/git.js

@@ -41,7 +41,12 @@ const downloadRepo = async repoPath => {
   }
 
   const tmpContents = await fs.readdir(tmpDir.path)
-  tmpDir.path = path.join(tmpDir.path, tmpContents[0])
+
+  const oldTemp = path.join(tmpDir.path, tmpContents[0])
+  const newTemp = path.join(tmpDir.path, pathParts.main.replace('/', '-'))
+
+  await fs.rename(oldTemp, newTemp)
+  tmpDir.path = newTemp
 
   return tmpDir
 }