Restore the key name

Author: yahonda

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby:
+        ruby-version:
           [
           '2.5',
           '2.6',
@@ -30,7 +30,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: ${{ matrix.ruby }}
+        ruby-version: ${{ matrix.ruby-version }}
         bundler-cache: true
         cache-version: 2
     - name: Run tests