Throw exe on empty python-version

src/setup-python.ts

@@ -53,6 +53,8 @@ async function run() {
       if (cache && isCacheFeatureAvailable()) {
         await cacheDependencies(cache, pythonVersion);
       }
+    } else {
+      throw new Error('there\'s empty python-version input')
     }
     const matchersPath = path.join(__dirname, '../..', '.github');
     core.info(`##[add-matcher]${path.join(matchersPath, 'python.json')}`);