Use v1 ruby checkout

Author: SleeplessByte

.github/workflows/debian.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Set up Ruby 2.7 (debian ruby)
-        uses: ruby/setup-ruby@v2
+        uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.7
       - name: Install dependencies