Update gem-push.yml

Author: pitbulk

.github/workflows/gem-push.yml

@@ -1,16 +1,16 @@
-name: Ruby Gem
+name: ruby-saml CI
 
 on: [push, pull_request]
 
 jobs:
   test:
     name: Unit test
-    runs-on: [ubuntu-latest, macos-latest]
     strategy:
-      fail_fast: false
+      fail-fast: false
       matrix:
-        ruby-version: [2.1.10, 2.2.10, 2.3.8, 2.4.6, 2.5.8, 2.6.6, 2.7.2, 3.0.1, jruby-9.1.17.0, jruby-9.2.17.0, truffleruby]
-
+        os: [ubuntu-latest, macos-latest]
+        ruby-version: [2.1.9, 2.2.10, 2.3.8, 2.4.6, 2.5.8, 2.6.6, 2.7.2, 3.0.1, jruby-9.1.17.0, jruby-9.2.17.0, truffleruby]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
       - name: Set up Ruby ${{ matrix.ruby-version }}