build(generated): dependabot for actions

Generated SDK source code using:
- Generator version 3.96.0
- Specification version 1.0.0-dev0.1.18
- Automation (cloudant-sdks) version 9bcd4ad

.github/dependabot.yml

@@ -1,5 +1,11 @@
 version: 2
 updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    pull-request-branch-name:
+      separator: "-"
   - package-ecosystem: "npm"
     directory: "/"
     open-pull-requests-limit: 10