ci: configure Renovate automerge with 3-day minimum release age (#41)

* Initial plan

* Configure Renovate to auto-merge updates after 3 days

Co-authored-by: deviantintegral <255023+deviantintegral@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: deviantintegral <255023+deviantintegral@users.noreply.github.com>

Author: Copilot

renovate.json

@@ -4,5 +4,7 @@
     "config:recommended",
     "helpers:pinGitHubActionDigests",
     ":enablePreCommit"
-  ]
+  ],
+  "automerge": true,
+  "minimumReleaseAge": "3 days"
 }