Configure Renovate (bazel-contrib#252)

* Add renovate.json

* Trunk fixes

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Siddhartha Bagaria <[email protected]>

Author: renovate[bot]

Diff for: renovate.json

@@ -0,0 +1,4 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": ["config:recommended"]
+}