Update README for limitation (#22)

README.md

@@ -20,4 +20,9 @@ Minimal setup.
 |---|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------|---|
 |`files`| A list of files with the path separated by a space, relative to root of your repository. Can also be a folder and the action will recursively pull all the files.              | `true`  |N/A|
 |`token`| A GitHub token.                                                                                                                                                                | `false` |`${{ github.token }}`|
-|`branch`| Checkout files from a specific branch.<br/> To use the current working branch `${{ github.head_ref \|\| github.ref_name }}`  |`false`|Default branch of the repository.|
+|`branch`| Checkout files from a specific branch. If not specified, it use the default repository branch.<br/> To use the current working branch `${{ github.head_ref \|\| github.ref_name }}`  |`false`|Default branch of the repository.|
+
+## Limitations
+
+* This action doesn't keep the mode bits (or permission) of files. See [#18](https://github.com/Bhacaz/checkout-files/issues/18) for more details.
+* Cannot pull files bigger than 1 mb. WIP [#3](https://github.com/Bhacaz/checkout-files/issues/3) & [#9](https://github.com/Bhacaz/checkout-files/issues/9)