Enable dependabot updates on a daily basis

using the `version update` label for gradle updates.

.github/dependabot.yml

@@ -0,0 +1,18 @@
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+  - package-ecosystem: "gradle"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    registries: "*"
+    labels: [ "version update" ]
+registries:
+  maven-google:
+    type: "maven-repository"
+    url: "https://maven.google.com"
+    replaces-base: true