Add dependabot configuration for weekly updates (#1988)

So far, only github-actions, docker, go and cargo will be checked

.github/dependabot.yml

@@ -0,0 +1,18 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "cargo"
+    directory: "/vm/rust"
+    schedule:
+      interval: "weekly"