Remplace CompatHelper with dependabot (#349)

Author: blegat

.github/dependabot.yml

@@ -0,0 +1,16 @@
+version: 2
+enable-beta-ecosystems: true
+updates:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "julia" # See documentation for possible values
+# # 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://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "weekly"