Update npm to v11 before publish

Because the OIDC flow needs v11

Author: tjenkinson

.github/workflows/build.yml

@@ -321,6 +321,10 @@ jobs:
         env:
           CI: true
 
+      # Publishing with OICD needs >= 11.5.1
+      - name: Update npm to v11
+        run: npm install -g npm@11
+
       - name: publish to npm
         run: |
           ./scripts/publish-npm.sh