ci: enable scheduled Renovate dependency updates

renovate.config.cjs

@@ -0,0 +1,6 @@
+module.exports = {
+  endpoint: "https://code.popov.link",
+  gitAuthor: "renovate[bot] <renovatebot@noreply.localhost>",
+  optimizeForDisabled: true,
+  platform: "gitea",
+};