Run old rubies with Ubuntu 20 in CI (#221)

* Run old rubies with Ubuntu 20 in CI

* Rename CI job for old Ubuntu

Author: arielj

.github/workflows/benchmarks.yml

@@ -12,9 +12,9 @@ jobs:
 
     strategy:
       matrix:
-        ruby-version: ['3.1', '3.0', '2.7', '2.5.1',  '2.4.3',  '2.3.0',
-                       '2.1.9',  '2.2.10', 'ruby-head', 'jruby-9.1.17.0',
-                       'jruby-head', 'truffleruby-22.3.0', 'truffleruby-head']
+        ruby-version: ['3.1', '3.0', '2.7', '2.5.1',  '2.4.3', 'ruby-head',
+                       'jruby-9.1.17.0', 'jruby-head', 'truffleruby-22.3.0',
+                       'truffleruby-head']
 
     steps:
       - name: Set Share Env
@@ -30,3 +30,25 @@ jobs:
         run: bundle install
       - name: Run benchmarks
         run: bundle exec rake
+
+  rake_old:
+    runs-on: ubuntu-20.04
+
+    strategy:
+      matrix:
+        ruby-version: ['2.3.0', '2.1.9', '2.2.10']
+
+    steps:
+      - name: Set Share Env
+        if: github.ref_name == 'main'
+        run: |
+          echo "SHARE=1" >> $GITHUB_ENV
+      - uses: actions/checkout@v3
+      - name: Set up Ruby ${{ matrix.ruby-version }}
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+      - name: Install dependencies
+        run: bundle install
+      - name: Run benchmarks
+        run: bundle exec rake