Merge pull request #15 from chatwork/dependabot/github_actions/actions/checkout-6

Bump actions/checkout from 4 to 6

Author: arai-ta

.github/workflows/ci.yml

@@ -24,10 +24,10 @@ jobs:
             composer: 2.2
           - php: 7.2
             phpunit: 6
-            composer: 2
+            composer: 2.2
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
 
       - uses: php-actions/composer@v6
         with: