Removed the deprecated test configurations

Author: hsbt

.github/workflows/macos.yml .github/workflows/coverage.yml.github/workflows/macos.yml renamed to .github/workflows/coverage.yml

@@ -1,18 +1,15 @@
-name: macos
+name: coverage
 
 on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: macos-latest
-    strategy:
-      matrix:
-        ruby: [ '3.0', 2.7, 2.6, ruby-head ]
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
     - uses: ruby/setup-ruby@v1
       with:
-        ruby-version: ${{ matrix.ruby }}
+        ruby-version: '3.0'
     - name: Install dependencies
       run: gem install minitest
     - name: Run test