Update npx build command

Author: LeeGathercole

.github/workflows/verify-build.yml

@@ -59,4 +59,4 @@ jobs:
         run: npm install ../../package.tgz
       - name: Build EventCatalog
         working-directory: examples/default/
-        run: npx nhso-eventcatalog build
+        run: npx @nhsdigital/nhso-eventcatalog-core build