Only save artifacts on merge to master

.gitlab-ci.yml

@@ -12,6 +12,14 @@ test_build_script:
   script:
     - shellcheck ./scripts/build.sh
 
+test_build_nginx:
+  stage: build
+  script:
+    - chmod +x ./scripts/build.sh
+    - ./scripts/build.sh
+  except:
+    - master
+
 build_nginx:
   stage: build
   script:
@@ -20,3 +28,5 @@ build_nginx:
   artifacts:
     paths:
       - src/nginx/objs/nginx
+  only:
+    - master