Update pom.xml

[mstahv]

Using the same working jetty version as in skeleton starter project. The one currently in use does not work due to asm incompatibilities.

Description

Please list all relevant dependencies in this section and provide summary of the change, motivation and context.

Fixes # (issue)

Type of change

• [ ] Bugfix
• [ ] Feature

Checklist

• [ ] I have read the contribution guide: https://vaadin.com/docs/latest/guide/contributing/overview/
• [ ] I have added a description following the guideline.
• [ ] The issue is created in the corresponding repository and I have referenced it.
• [ ] I have added tests to ensure my change is effective and works as intended.
• [ ] New and existing tests are passing locally with my change.
• [ ] I have performed self-review and corrected misspellings.

Additional for Feature type of change

• [ ] Enhancement / new feature was discussed in a corresponding GitHub issue and Acceptance Criteria were created.