chore/add-dependabot (#232)

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## Description

Added `dependabot` configuration, which notifies us of any updated
dependencies, and if there is security aspects that we'd need to take
care of.

## Type of Change

<!--- Put an `x` in all the boxes that apply: -->

- [x] 🗑️ Chore

.github/.github/dependabot.yaml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+  - package-ecosystem: "pub"
+    directory: "/"
+    schedule:
+      interval: "daily"