build: update dependabot.yml (#208)

Author: icweaver

.github/dependabot.yml

@@ -5,3 +5,13 @@ updates:
     directory: "/" # Location of package manifests
     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:
+          - "*"
+    ignore:
+      - dependency-name: "JuliaAstroDocs" # Ignore package itself