build: auto-approve renovate-bot PRs for minor updates (#1145)

Author: sofisl

synthtool/gcp/templates/node_library/.github/auto-approve.yml

@@ -4,4 +4,9 @@ rules:
   changedFiles:
   - "package\\.json$"
   - "CHANGELOG\\.md$"
-  maxFiles: 3
+  maxFiles: 3
+- author: "renovate-bot"
+  title: "^(fix\\(deps\\)|chore\\(deps\\)):"
+  changedFiles: 
+  - "/package\\.json$"
+  maxFiles: 2