chore: enable dependabot

. Check GitHub Actions, Go modules and Docker

.github/dependabot.yml

@@ -0,0 +1,16 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "daily"
+
+  - package-ecosystem: "docker"
+    directory: "/.github/go"
+    schedule:
+      interval: "daily"

.github/go/Dockerfile

@@ -0,0 +1 @@
+FROM golang:1.14.3