fix ci and update readme

Author: DannyBen

.github/workflows/test.yml

@@ -9,6 +9,9 @@ jobs:
 
     runs-on: ubuntu-latest
 
+    env: 
+      LC_ALL: en_US.UTF-8 # consistent sort order
+
     strategy:
       matrix: { ruby: ['2.4', '2.5', '2.6', '2.7', '3.0'] }
 

README.md

@@ -223,6 +223,7 @@ bash function.
 `help`     | The message to display when using `--help`. Can have multiple lines.
 `required` | Specify if this argument is required. Note that once you define an optional argument (without required: true) then you cannot define required arguments after it.
 `default`  | The value to use in case it is not provided by the user. Implies that this argument is optional.
+`allowed`  | Limit the allowed values by providing an array.
 
 ### Flag options