Log timestamps with milliseconds by default

.env.template

@@ -46,7 +46,7 @@
 
 ## Timestamp format used in extended logging.
 ## Format specifiers: https://docs.rs/chrono/latest/chrono/format/strftime
-# LOG_TIMESTAMP_FORMAT="%Y-%m-%d %H:%M:%S"
+# LOG_TIMESTAMP_FORMAT="%Y-%m-%d %H:%M:%S.%3f"
 
 ## Logging to file
 ## It's recommended to also set 'ROCKET_CLI_COLORS=off'

src/config.rs

@@ -330,7 +330,7 @@ make_config! {
         /// Enable extended logging
         extended_logging:       bool,   false,  def,    true;
         /// Log timestamp format
-        log_timestamp_format:   String, true,   def,    "%Y-%m-%d %H:%M:%S".to_string();
+        log_timestamp_format:   String, true,   def,    "%Y-%m-%d %H:%M:%S.%3f".to_string();
         /// Enable the log to output to Syslog
         use_syslog:             bool,   false,  def,    false;
         /// Log file path