feat: experimenting with automated release post to Mastodon (#166)

see title

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

- **New Features**
- Introduced an automated workflow to post updates to Mastodon when a
pull request is merged into the main branch.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

.github/workflows/post_to_mastodon.yml

@@ -0,0 +1,31 @@
+name: Post to Mastodon on PR Merge
+
+on:
+  pull_request:
+    branches:
+      - main
+    types:
+      - closed
+
+permissions:
+  pull-requests: read
+
+jobs:
+  post_to_mastodon:
+    if: github.event.pull_request.merged == true
+    runs-on: ubuntu-latest
+    steps:
+      - name: Post to Mastodon
+        uses: nick-fields/retry@v2
+        with:
+          timeout_minutes: 2
+          max_attempts: 3
+          command: |
+                     curl -X POST -H "Authorization: Bearer ${{ secrets.MASTODON_ACCESS_TOKEN }}" \
+                     -F "status=New release in Snakemake project '${{ github.event.repository.full_name }}' for pull request '#${{ github.event.pull_request.number }}' merged: '${{ github.event.pull_request.title }}'. Get the latest release from #Bioconda or #Pypi." \
+                     https://fediscience.org/api/v1/statuses \
+                     -w "\nResponse code: %{http_code}\n" \
+                     -f || {
+                       echo "Failed to post to Mastodon"
+                       exit 1
+                     }