replace CompatHelper with dependabot

Author: lkdvos

.github/dependabot.yml

@@ -0,0 +1,14 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "julia"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    groups: # uncomment to group all julia package updates into a single PR
+      all-julia-packages:
+        patterns:
+          - "*"