Add input to allow signing release commits

Author: h-haaks

.github/workflows/prepare_release.yml

@@ -14,6 +14,11 @@ on:
         required: false
         default: ''
         type: string
+      sign-commits:
+        description: 'Sign commits as `github-actions[bot]` when using `GITHUB_TOKEN`, or your own bot when using GitHub App tokens.'
+        required: false
+        default: false
+        type: boolean
       working-directory:
         description: The working directory where all jobs should be executed. Used for modules in subdirectories like a monorepo or a control repository.
         default: '.'
@@ -74,6 +79,7 @@ jobs:
           commit-message: "Release ${{ inputs.version }}"
           branch: release-prep
           delete-branch: true
+          sign-commits: ${{ inputs.sign-commits }}
           title: "Release ${{ inputs.version }}"
           labels: skip-changelog
           token: '${{ secrets.github_pat }}'