Create dependabot.yml

In response to #13600. Setting a software defined policy around NPM dependencies
- This is the first step to taking in inventory of dependencies

Author: zoracon

.github/dependabot.yml

@@ -0,0 +1,20 @@
+version: 2
+updates:
+  # Maintain dependencies for npm
+  - package-ecosystem: "npm"
+    directory: "/chromium/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+      time: "06:00"
+    assignees:
+      - "zoracon"
+    commit-message:
+      prefix: "npmauto"
+    labels:
+      - "dependencies"
+    pull-request-branch-name:
+      separator: "-"
+    reviewers:
+      - "zoracon"
+    versioning-strategy: widen