fix: ruby-version-file を ruby-version に修正

Author: nacchan99

.github/workflows/fetch_news.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version-file: .ruby-version
+          ruby-version: .ruby-version
           bundler-cache: true
 
       - name: Install dependencies