add dependabot config file

.github/dependabot.yml

@@ -0,0 +1,19 @@
+# Reference:
+#   - https://docs.github.com/en/code-security/supply-chain-security/keeping-your-dependencies-updated-automatically/keeping-your-actions-up-to-date-with-dependabot
+
+version: 2
+updates:
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    target-branch: "dependencies"
+    labels: ["dependencies"]
+
+  - package-ecosystem: "pip"
+    directory: "/requirements"
+    schedule:
+      interval: "daily"
+    target-branch: "dependencies"
+    labels: ["dependencies"]