fix: use escaped newlines in PR body to avoid YAML parsing error

.gitea/workflows/nix-update.yml

@@ -178,20 +178,12 @@ env:
           # Get commit messages for PR description
           COMMITS=$(git log origin/master..origin/"${BRANCH}" --pretty=format:"%h %s" | sed 's/^/- /')
 
-          PR_BODY="Automated package updates using nix-update.
-
-Updated packages:
-${PACKAGES}
-
-Commits:
-${COMMITS}"
-
           # Create PR
           /tmp/tea pr create \
             --head "${BRANCH}" \
             --base master \
             --title "chore: update packages with nix-update" \
-            --body "${PR_BODY}" \
+            --body "Automated package updates using nix-update.\n\nUpdated packages:\n${PACKAGES}\n\nCommits:\n${COMMITS}" \
             --assignees m3tam3re \
             --labels automated-update || echo "Failed to create PR. Please create manually."