chore: add rollup group to Dependabot configuration (#60)

chore(actions): add `rollup` group to Dependabot configuration

Author: panz3r

.github/dependabot.yml

@@ -27,3 +27,7 @@ updates:
       babel:
         patterns:
           - "@babel/*"
+      rollup:
+        patterns:
+          - "rollup"
+          - "@rollup/*"