fix: secret in workflow (#269)

bumped action version to correct version

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

## Summary by CodeRabbit

- **Chores**
- Updated the workflow for announcing releases on Mastodon to use the
latest version of the related GitHub Action.

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

Author: cmeesters

.github/workflows/announce-release.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Post to Mastodon
-        uses: snakemake/[email protected].4
+        uses: snakemake/[email protected].5
 
         with:
           access-token: ${{ secrets.MASTODONBOT }}