feat: mastodonbot (#185)

like #183 - there is a mismatch in the allowed commands

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
	- Added an automated script to post release announcements to Mastodon
- Implemented a GitHub Actions workflow to trigger Mastodon
announcements after pull request merges

- **Chores**
	- Updated `.gitignore` to include new file exclusion patterns
- Refined release announcement process with improved error handling and
messaging

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: cmeesters

.github/workflows/post_to_mastodon.yml

@@ -20,7 +20,7 @@ jobs:
         with:
           timeout_minutes: 2
           max_attempts: 3
-          run: |
+          command: |
             git checkout ${{ github.event.pull_request.head.sha }}
             export MASTODONBOT="${{ secrets.MASTODONBOT }}"
             export PR_TITLE="${{ github.event.pull_request.title }}"