fix: resolve YAML syntax error in PR body

.gitea/workflows/nix-update.yml

@@ -178,18 +178,20 @@ 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 "${BRANCH}" \
             --base master \
             --title "chore: update packages with nix-update" \
-            --body "Automated package updates using nix-update.
-
-**Updated packages:**
-${PACKAGES}
-
-**Commits:**
-${COMMITS}" \
+            --body "${PR_BODY}" \
             --assignees m3tam3re \
             --labels automated-update || echo "Failed to create PR. Please create manually."