Add Renovate (#8) [skip-ci]

Fixes #4

Reviewed-on: #8

renovate.json

@@ -0,0 +1,8 @@
+{
+    "extends": [":automergeMinor", ":automergePr", ":automergeRequireAllStatusChecks", ":dependencyDashboard", ":disableRateLimiting", ":rebaseStalePrs"],
+    "baseBranches": ["master"],
+    "major": {
+        "dependencyDashboardApproval": true
+    },
+    "minimumReleaseAge": "7 days"
+}