Make it quit early, also only install dev dependencies

appveyor.yml

@@ -49,8 +49,11 @@ build_script:
           rm base
           cp -Rf ../base ./base
 
-          npm install
+          npm install --only=dev
+          if [ $? -ne 0 ]; then continue; fi;
+
           npm run build
+          if [ $? -ne 0 ]; then continue; fi;
 
           ./7zas a -xr!*.xcf -mx9 "${CURR_VER}_build-sc.7z" package.json index.mjs api base public
           echo "Creating release on gitea"