Create dependabot.yml

Adds dependabot configuration. Satisfies Dependency-Update-Tool OpenSSF scorecard requirement. Requires repository settings changes to function properly.

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "weekly"