ci.yml in prosopite-1.3.0

- old
+ new

@@ -2,10 +2,10 @@
 on: [push, pull_request]
 jobs:
   test:
     strategy:
       matrix:
-        ruby: [2.5, 2.6, 2.7, '3.0', 3.1, head]
+        ruby: [2.7, '3.0', 3.1, head]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with: