Fix matrix

Author: Israphel

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby:
+        version:
           - '2.5.0'
           - '3.1.1'
 
@@ -35,10 +35,10 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Setup Ruby ${{ matrix.ruby }}
+      - name: Setup Ruby ${{ matrix.version }}
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: ${{ matrix.ruby }}
+          ruby-version: ${{ matrix.version }}
 
       - name: Install dependencies
         run: bundle install