Modified the pipeline

.gitea/workflows/ci.yml

@@ -5,5 +5,6 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v4
       - name: Printing hello
-        run: echo "Hello, World!"
+        run: gcc -Wall -Werror main.c

main.c

@@ -0,0 +1,4 @@
+int main() {
+    printf("Hello, World!");
+    return 0;
+}