Use heredoc to safely dump markdown

Author: jayqi

.github/workflows/release.yml

@@ -1,4 +1,5 @@
 name: release
+run-name: Release of ${{ inputs.version }}
 
 on:
   workflow_dispatch:
@@ -51,7 +52,9 @@ jobs:
 
       - name: Write output to file
         run: |
-          printf '${{ steps.extract-changelog.outputs.markdown }}' > __CHANGELOG-extracted.md
+          cat <<'__EOF__' > __CHANGELOG-extracted.md
+          ${{ steps.extract-changelog.outputs.markdown }}
+          __EOF__
 
       - uses: ncipollo/release-action@v1
         with: