port generic Renovate options from gitea's renovate.json5 (#545)

Ports repo-agnostic options from gitea/gitea's `renovate.json5`:

- `default.json`: `minimumReleaseAge: "5 days"`, `configMigration: true`
- `go-deps.json`: `gomodUpdateImportPaths` postUpdateOption + immediate Go toolchain bumps (opt-in preset, no-op without `go.mod`)
- `npm-deps.json`: `pnpmDedupe` postUpdateOption (no-op for non-pnpm repos)

Reviewed-on: https://gitea.com/gitea/renovate-config/pulls/545
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-committed-by: silverwind <me@silverwind.io>

npm-deps.json

@@ -3,6 +3,9 @@
   "npm": {
     "enabled": true
   },
+  "postUpdateOptions": [
+    "pnpmDedupe"
+  ],
   "packageRules": [
     {
       "groupName": "npm dependencies",