chore: Add change-master-password command doc

docs/commands/change-master-password.md

@@ -1,3 +1,32 @@
 # Changing the master password
 
 ## Usage
+
+```
+Usage: lprs change-master-password [NEW_PASSWORD]
+
+Arguments:
+  [NEW_PASSWORD]  The new master password, if there is no value for it you will prompt it
+
+Options:
+  -h, --help  Print help
+```
+
+A command to change the master password of the vaults file, you can provide the
+new password as an argument or you will be prompted for it.
+
+### Example
+Prompt for the new master password
+```bash
+lprs change-master-password
+```
+
+Change the master password to `new-password`
+```bash
+lprs change-master-password 'new-password'
+```
+
+## Note
+- The master password is used to encrypt and decrypt the vaults file, so if you
+  forget it you will lose all your vaults.
+- This action is irreversible, so make sure to remember the new password.