Switch to specific spectral action

Author: ojousima

.github/workflows/openapi.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       # Check out the repository
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
 
       # Run Spectral
       - uses: stoplightio/spectral-action@latest