Create dependabot.yml (#2276)

.github/dependabot.yml

+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: gomod # See documentation for possible values
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly
+  - package-ecosystem: docker
+    directory: "/build"
+    schedule:
+      interval: weekly