[RELEASE] Bump bk version to 4.7.1 in docker file

[sijie]

Descriptions of the changes in this PR:

Bump bk version to 4.7.1 to build docker image for 4.7.1

Author: Sijie Guo sijie@apache.org

Reviewers: Jia Zhai

This closes #1523 from sijie/bump_docker_version

---

In order to uphold a high standard for quality for code contributions, Apache BookKeeper runs various precommit
checks for pull requests. A pull request can only be merged when it passes precommit checks. However running all
the precommit checks can take a long time, some trivial changes don't need to run all the precommit checks. You
can check following list to skip the tests that don't need to run for your pull request. Leave them unchecked if
you are not sure, committers will help you:

• [skip bookkeeper-server bookie tests]: skip testing org.apache.bookkeeper.bookie in bookkeeper-server module.
• [skip bookkeeper-server client tests]: skip testing org.apache.bookkeeper.client in bookkeeper-server module.
• [skip bookkeeper-server replication tests]: skip testing org.apache.bookkeeper.replication in bookkeeper-server module.
• [skip bookkeeper-server tls tests]: skip testing org.apache.bookkeeper.tls in bookkeeper-server module.
• [skip bookkeeper-server remaining tests]: skip testing all other tests in bookkeeper-server module.
• [skip integration tests]: skip docker based integration tests. if you make java code changes, you shouldn't skip integration tests.
• [skip build java8]: skip build on java8. ONLY skip this when ONLY changing files under documentation under site.
• [skip build java9]: skip build on java9. ONLY skip this when ONLY changing files under documentation under site.

---

[sijie]

just realized that docker change #1529 is not cherry-picked back forgot to master.

This is the cherry-pick PR for #1529