ci: add dependabot (#305)

Author: timerring

.github/dependbot.yml

@@ -0,0 +1,16 @@
+# https://docs.github.com/en/code-security/dependabot/working-with-dependabot/dependabot-options-reference#package-ecosystem
+version: 2
+updates:
+  - package-ecosystem: "npm"
+    # Look for `package.json` and `lock` files in the `root` directory
+    directory: "/"
+    # Check the npm registry for updates every day (weekdays)
+    schedule:
+      interval: "daily"
+
+  - package-ecosystem: "pip"
+    # Look for a `requirements.txt` in the `root` directory
+    directory: "/"
+    # Check for updates once a week
+    schedule:
+      interval: "weekly"