Try adding cmd.exe example

Author: ehmicky

examples/convert.cmd

@@ -0,0 +1,14 @@
+:: This example demonstrates the `convert` command in the Windows default
+:: terminal (`cmd.exe`).
+:: This file can be directly run:
+::   - first install `unix-permissions`
+::   - then `cmd /q /d /s /c node_modules\unix-permissions\examples\convert.cmd`
+
+call npx unix-permissions convert.symbolic 111
+:: a=x
+
+call npx unix-permissions convert.octal o+x
+:: +0001
+
+call npx unix-permissions convert.octal o=x
+:: 0001