chore: configure dependency bots to group all updates into single PR

Configure both Dependabot and Renovate to combine all dependency
updates into a single PR instead of creating individual PRs per package.

Author: gegles

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    groups:
+      all-dependencies:
+        patterns:
+          - "*"

renovate.json

@@ -2,5 +2,11 @@
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": [
     "config:recommended"
+  ],
+  "packageRules": [
+    {
+      "matchPackagePatterns": ["*"],
+      "groupName": "all-dependencies"
+    }
   ]
 }