Tweak dependabot config

* switch to weekly updates
* increase versions
* add bundler deps too

.github/dependabot.yml

@@ -1,8 +1,18 @@
 version: 2
 updates:
-- package-ecosystem: npm
+  - package-ecosystem: npm
-  directory: "/"
+    directory: "/"
-  schedule:
+    schedule:
-    interval: daily
+      interval: weekly
-    time: "03:00"
+      day: monday
-  open-pull-requests-limit: 10
+      time: "03:00"
+    open-pull-requests-limit: 10
+    versioning-strategy: increase
+  - package-ecosystem: bundler
+    directory: "/docs/"
+    schedule:
+      interval: weekly
+      day: monday
+      time: "03:00"
+    open-pull-requests-limit: 10
+    versioning-strategy: increase