chore: Add Renovate config

Author: nzakas

.github/renovate.json5

@@ -0,0 +1,19 @@
+{
+	$schema: "https://docs.renovatebot.com/renovate-schema.json",
+	// see https://docs.renovatebot.com/presets-config/
+	extends: [
+		"config:base",
+		// automatically rebase onto main branch
+		":rebaseStalePrs",
+		// groups all ESLint-related dependency upgrades into a single PR
+		"group:linters",
+	],
+	packageRules: [
+		// only send upgrade for deps (from the npm registry) after they've been
+		// published for 30 days
+		{
+			matchDatasources: ["npm"],
+			minimumReleaseAge: "30 days",
+		},
+	],
+}