Update npm-publish.yml

Author: vermorag

.github/workflows/npm-publish.yml

@@ -17,7 +17,8 @@ jobs:
         with:
           node-version: 20
           registry-url: https://registry.npmjs.org/
-
+      - name: Update npm
+        run: npm install -g npm@latest
       - run: npm ci
       - run: npm run build-themes
       - run: npm publish