feat: support action failure on bad revision

README.md

@@ -4,6 +4,9 @@
 
 Produce short revision environment variable based on the input one.
 
+If a revision is a bad revision, this action will produce an error message and fail depending on `continue-on-error` input value.
+`<NAME>`, and `<NAME>_SHORT` environment variable will only be available if the revision is not empty and valid.
+
 ## Usage
 
 - Shortify an environment variable
@@ -31,3 +34,22 @@ Produce short revision environment variable based on the input one.
 
   - `SOME_REVISION`
   - `SOME_REVISION_SHORT`
+
+## Inputs
+
+### `name`
+
+If used with `revision` input, it's the name of the environment variable containing the revision to shortify.
+Otherwise, the `name` input will be used (in upper case) to define a environment variable containing the `revision` input value.
+
+### `revision`
+
+The revision to shortify into an environment variable named `<NAME>_SHORT`.
+
+This input is _Optional_.
+
+### `continue-on-error`
+
+If the input is set to `true`, this action will not fail on a bad revision
+
+The default value is `false`.