Update dependabot

Author: montyly

.github/dependabot.yml

@@ -4,3 +4,23 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+  - package-ecosystem: "gitsubmodule"
+    directory: "/program-analysis/medusa"
+    schedule:
+      interval: "daily" # Check for updates daily
+    commit-message:
+      prefix: "Update medusa"
+    assignees:
+      - ggrieco-tob
+    reviewers:
+      - ggrieco-tob
+  - package-ecosystem: "gitsubmodule"
+    directory: "/program-analysis/slither"
+    schedule:
+      interval: "daily" # Check for updates daily
+    commit-message:
+      prefix: "Update slither"
+    assignees:
+      - ggrieco-tob
+    reviewers:
+      - ggrieco-tob