ci: fix node version to support OIDC

Author: PierreJeanjacquot

.github/workflows/sdk-publish-npm.yml

@@ -40,7 +40,7 @@ jobs:
     with:
       scope: '@iexec/dataprotector'
       registry: 'https://registry.npmjs.org'
-      node-version: '18'
+      node-version: '20'
       environment: 'staging'
       working-directory: packages/sdk
       tag: 'nightly'
@@ -56,7 +56,7 @@ jobs:
     with:
       scope: '@iexec/dataprotector'
       registry: 'https://registry.npmjs.org'
-      node-version: '18'
+      node-version: '20'
       working-directory: packages/sdk
       tag: 'latest'
       install-command: |