Merge pull request #217 from projekteuler/ruby-3.0

Update Ruby version and Node action for CI

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: ['2.5', '2.6', '2.7']
+        ruby: ['2.6', '2.7', '3.0']
     steps:
       - uses: actions/checkout@v2
       - name: Set up Ruby ${{ matrix.ruby }}
@@ -17,7 +17,7 @@ jobs:
           ruby-version: ${{ matrix.ruby }}
           bundler-cache: true
       - name: Set up Node
-        uses: actions/setup-node@v2-beta
+        uses: actions/setup-node@v2
         with:
           node-version: '14'
       - name: Install dependencies