fix: full release notes (#306)

Author: cmeesters

.github/workflows/announce-release.yml

@@ -19,7 +19,7 @@ jobs:
         id: extract-release-notes
         uses: ffurrer2/extract-release-notes@v2
         with:
-          changelog_file: CHANGELOG.md
+          changelog_file: ${GITHUB_WORKSPACE}/CHANGELOG.md
       - name: Post to Mastodon
         uses: snakemake/mastodon-release-post-action@v1.2.3
         with: