feat: add an option to configure Sanity authentication token

.env.example

@@ -18,6 +18,7 @@ EMAIL_CONTACT_ADDRESS=
 EMAIL_CONTACT_DEST=
 
 NEXT_PUBLIC_SANITY_PROJECT_ID=
+SANITY_AUTH_TOKEN=
 SANITY_WEBHOOK_SECRET=
 
 NEXT_PUBLIC_HCAPTCHA_SITE_KEY=

lib/sanity.ts

@@ -5,6 +5,7 @@ const config = {
   apiVersion: "2023-08-08",
   dataset: "production",
   projectId: `${process.env.NEXT_PUBLIC_SANITY_PROJECT_ID}`,
+  token: `${process.env.SANITY_AUTH_TOKEN}`,
   useCdn: false // ensure fresh data
 };