fix: Pass arguments

The INPUTS_* environment variables are not present in composite actions.
A flag interface seems more intuitive for local testing too.

action.yml

@@ -8,4 +8,4 @@ runs:
   using: "composite"
   steps:
     - shell: bash
-      run: ${{ github.action_path }}/nix-develop-gha.sh
+      run: ${{ github.action_path }}/nix-develop-gha.sh ${{ inputs.arguments }}

nix-develop-gha.sh

@@ -2,8 +2,8 @@
 
 set -euo pipefail
 
-# Read the arguments input into an array, so it can be added to a command line.
-IFS=" " read -r -a arguments <<<"${INPUT_ARGUMENTS:-}"
+# Read the arguments into an array, so they can be added correctly as flags
+IFS=" " read -r -a arguments <<<"${@:-}"
 
 with_nix_develop() {
 	nix develop --ignore-environment "${arguments[@]}" --command "$@"