Enable dependabot dependency updates

Configure Dependabot automatic dependency upgrades.

Author: software-artificer

.github/dependabot.yml

@@ -0,0 +1,16 @@
+version: 2
+updates:
+- package-ecosystem: "github-actions"
+  directory: "/"
+  schedule:
+    interval: "weekly"
+    day: "saturday"
+    time: "04:00"
+    timezone: "Australia/Sydney"
+- package-ecosystem: "cargo"
+  directory: "/"
+  schedule:
+    interval: "weekly"
+    day: "saturday"
+    time: "04:00"
+    timezone: "Australia/Sydney"