docs(README): add recursive flag options

Signed-off-by: jmattaa <mattajonathan1@gmail.com>

README.md

@@ -78,6 +78,9 @@ you can directly pass in the flags.
 - `-S` or `--Symlinks` shows only symlinks
 - `-G` or `--Git` shows only the entries that are not named in `.gitignore` (works only if there exists a `.gitignore`)
 - `-r` or `--recursive` shows directory tree structure
+    - `-r` or `--recursive` has an optional value for max depth and  it can be 
+    used by using `-r2` or `--recursive=2` by default the depth is until last 
+    level
 
 
 The flags can be chained for example using: