update .env for sentry

src/schedule-2.0/.env

@@ -61,4 +61,7 @@ CAS_FIRSTNAME=firstname
 # For Gmail as a transport, use: "gmail://username:password@localhost"
 # For a generic SMTP server, use: "smtp://localhost:25?encryption=&auth_mode="
 # Delivery is disabled by default via "null://localhost"
-MAILER_URL=
+MAILER_URL=
+
+## Sentry DSN
+SENTRY_DSN=