Some minor pom clean-ups

[bashir2]

Description of what I changed

This was an attempt to fix #939 but unfortunately it does not change the uber jar sizes much; but it fixes some warning messages during build. Some of the bigger dependencies that might be worth shrinking like beam-sdks-java-io-google-cloud-platform (over 100 MB) needs more testing that are not covered by our e2e, so I left them intact.

E2E test

TESTED:

Please replace this with a description of how you tested your PR beyond the automated e2e/unit tests.

Checklist: I completed these to help reviewers :)

• [x] I have read and will follow the review process.

• [x] I am familiar with Google Style Guides for the language I have coded in.

  No? Please take some time and review Java and Python style guides.

• [x] My IDE is configured to follow the Google code styles.

  No? Unsure? -> configure your IDE.

• [ ] I have added tests to cover my changes. (If you refactored existing code that was well tested you do not have to add tests)

• [x] I ran mvn clean package right before creating this pull request and added all formatting changes to my commit.

• [x] All new and existing tests passed.

• [x] My pull request is based on the latest changes of the master branch.

  No? Unsure? -> execute command git pull --rebase upstream master

[chandrashekar-s]

The build is failing due to some regression introduced by the latest HAPI release. This is fixed by the PR https://github.com/google/fhir-data-pipes/pull/970. We can rebuild this once the fix is merged.