Use ruby-version over the now-deprecated version

.github/workflows/ruby.yml

@@ -15,7 +15,7 @@ jobs:
     - name: Set up Ruby ${{ matrix.ruby }}
       uses: actions/setup-ruby@v1
       with:
-        version: ${{ matrix.ruby }}
+        ruby-version: ${{ matrix.ruby }}
     - name: Build and test
       run: |
         gem install bundler