Reduce dependabot bumps for aws-java-sdk to weekly

[Vlatombe]

Most of the time new versions don't contain relevant changes for this library (I mostly monitor for new EC2 instance types, which are necessary to the ec2-plugin). So instead of having daily noise, it will only be weekly now.

Testing done

### Submitter checklist
- [ ] Make sure you are opening from a **topic/feature/bugfix branch** (right side) and not your main branch!
- [ ] Ensure that the pull request title represents the desired changelog entry
- [ ] Please describe what you did
- [ ] Link to relevant issues in GitHub or Jira
- [ ] Link to relevant pull requests, esp. upstream and downstream changes
- [ ] Ensure you have provided tests - that demonstrates feature works or fixes the issue