add hubspot to newsletter

[netlify[bot]]

✅ Deploy Preview for substrate-website ready!

Name	Link
🔨 Latest commit	c521ed08c72049efee13cfdb2cded980260df8f3
🔍 Latest deploy log	https://app.netlify.com/sites/substrate-website/deploys/62d144de1d3450000884789c
😎 Deploy Preview	https://deploy-preview-269--substrate-website.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.