Add renovate

Author: notpeter

renovate.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended",
+    ":semanticCommitsDisabled",
+    ":separateMultipleMajorReleases",
+    "helpers:pinGitHubActionDigests",
+    "group:serdeMonorepo"
+  ],
+  "timezone": "America/New_York",
+  "schedule": ["after 3pm on Wednesday"]
+}