add uses int yml

.github/workflows/c-cpp.yml

@@ -2,16 +2,14 @@ name: C/C++ CI
 
 on:
   push:
-    branches: [ "main", "dev" ]
-  pull_request:
-    branches: [ "main" ]
 
 jobs:
   build:
 
     runs-on: ubuntu-latest
 
     steps:
+    - uses: actions/checkout@v1
     - name: check the environment
       run: g++ --version && git --version && bash --version
     - name: list the environment