Added '-l' CLI flag description to --help

usage.txt

@@ -9,8 +9,13 @@
 
      cat log | pino -t
 
+  To flip level and time/date in standard output use the -l flag
+
+     cat log | pino -l
+
   Flags
   -h | --help      Display Help
   -v | --version   Display Version
   -t               Convert Epoch timestamps to ISO
+  -l               Flip level and date