ci(netlify): set default cache-control

source/_headers

@@ -1,4 +1,5 @@
 /*
+  Cache-Control: max-age=86400, public
   Clear-Site-Data: "cookies", "storage"
   Content-Language: en-GB
   Content-Security-Policy: default-src 'self'; child-src 'none'; connect-src 'none'; font-src 'none'; frame-src 'none'; img-src 'self'; manifest-src 'none'; media-src 'none'; object-src 'none'; prefetch-src 'none'; script-src 'self'; style-src 'self'; worker-src 'none'; base-uri 'none'; form-action https://duckduckgo.com https://3g2upl4pq6kufc4m.onion; frame-ancestors 'none'; block-all-mixed-content