.github/workflows/test.yml in sengiri_yaml-0.0.4 vs .github/workflows/test.yml in sengiri_yaml-1.0.0.rc1

@@ -10,13 +10,10 @@
       - synchronize
       - reopened
   schedule:
     - cron: "0 10 * * 5" # JST 19:00 (Fri)
 
-env:
-  CI: "true"
-
 jobs:
   test:
     runs-on: ubuntu-latest
 
     container: ${{ matrix.ruby }}
@@ -24,25 +21,20 @@
     strategy:
       fail-fast: false
 
       matrix:
         ruby:
-          - ruby:2.1
-          - ruby:2.2
-          - ruby:2.3
-          - ruby:2.4
-          - ruby:2.5
           - ruby:2.6
           - ruby:2.7
           - ruby:3.0
+          - ruby:3.1
           - rubylang/ruby:master-nightly-bionic
         include:
           - ruby: rubylang/ruby:master-nightly-bionic
             allow_failures: "true"
 
     steps:
       - uses: actions/checkout@v2
-
 
       - name: Cache vendor/bundle
         uses: actions/cache@v1
         id: cache_gem
         with: