Don't use an external script for multiple inputs

All consumers would then have to bring this script into their repo,
since GitHub doesn't have something like Nix's string context.

.github/workflows/ci.yml

@@ -1,17 +0,0 @@
-name: CI
-on:
-  pull_request:
-  push:
-    branches: [main]
-
-jobs:
-  shellcheck:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          fetch-depth: 0
-      - name: Install Nix
-        uses: cachix/install-nix-action@v16
-      - name: Shellcheck
-        run: nix-shell --run 'shellcheck $(find . -type f -name "*.sh" -executable)'

.github/workflows/update.yml

@@ -1,19 +0,0 @@
-name: update-flake-lock
-on:
-  workflow_dispatch:
-  schedule:
-    - cron: '0 0 * * 0'
-
-jobs:
-  lockfile:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v2
-      - name: Install Nix
-        uses: cachix/install-nix-action@v16
-        with:
-          extra_nix_config: |
-            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
-      - name: Update flake.lock
-        uses: ./.

action.yml

@@ -8,7 +8,16 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - run: ./update-input-or-inputs.sh ${{ inputs.inputs }}
+    - run: |
+        if [[ -n '${{ inputs.inputs }}' ]]; then
+          inputs=()
+          for input in ${{ inputs.inputs }}; do
+            inputs+=("--update-input" "$input")
+          done
+          nix flake lock "${inputs[@]}" --commit-lock-file
+        else
+          nix flake update --commit-lock-file
+        fi
       shell: bash
       env:
         GIT_AUTHOR_NAME: github-actions[bot]

update-input-or-inputs.sh

@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-to_update=$*
-
-if [ -n "$to_update" ]; then
-  inputs=()
-  for input in $to_update; do
-    inputs+=("--update-input" "$input")
-  done
-  nix flake lock "${inputs[@]}" --commit-lock-file
-else
-  nix flake update --commit-lock-file
-fi