Update pandoc/core Docker tag to v2.12 (#99)

Co-authored-by: Renovate Bot <[email protected]>

Author: renovate[bot]

.github/workflows/sync-doc-assets.yml

@@ -14,7 +14,7 @@ jobs:
           fetch-depth: 0
 
       - name: Copy CHANGELOG
-        uses: docker://pandoc/core:2.9
+        uses: docker://pandoc/core:2.12
         with:
           args: -t markdown CHANGELOG.md -t rst --output=docs/source/changelog.rst