CI: Enable Dependabot (#18)

-- begin release notes --
Enable Dependabot
-- end release notes --

.github/dependabot.yml

@@ -0,0 +1,18 @@
+version: 2
+updates:
+  # Enable version updates for nuget
+  - package-ecosystem: "nuget"
+    # Look for NuGet dependency info from the `root` directory
+    directory: "/"
+    registries: "*"
+    # Check the nuget registry for updates every day (weekdays) schedule:
+    schedule:
+      timezone: "America/Chicago"
+      time: "22:00"
+      interval: "daily"
+
+registries:
+  nuget:
+    type: "nuget-feed"
+    url: https://api.nuget.org/v3/index.json
+    token: ${{ secrets.DEPENDABOT_NUGET_RESTORE_PASSWORD }}