chore: Update font source in Content-Security-Policy

Author: giovanninocco

layouts/index.headers

@@ -2,7 +2,7 @@
   Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
   X-Content-Type-Options: nosniff
   X-XSS-Protection: 1; mode=block
-  Content-Security-Policy: frame-src * data: blob: ; frame-ancestors https://jamstackthemes.dev; manifest-src 'self' https://*.netlify.app; connect-src 'self' https://*.netlify.app; font-src 'self' https://*.netlify.app; style-src 'self' https://*.netlify.app 'unsafe-inline'
+  Content-Security-Policy: frame-src * data: blob: ; frame-ancestors https://jamstackthemes.dev; manifest-src 'self' https://*.netlify.app; connect-src 'self' https://*.netlify.app; font-src 'self' https://fonts.googleapis.com; style-src 'self' https://*.netlify.app 'unsafe-inline'
   X-Frame-Options: SAMEORIGIN
   Referrer-Policy: strict-origin
   Feature-Policy: geolocation 'self'