Swap java8-multiarch into java8 image tag

### Enhancement Type

Improve an existing feature

### Describe the enhancement

Keep java8-multiarch image tag but also tag it as java8 to avoid the stale version of java 8 that the alpine upstream supplies.

Inspect the Docker image build and tagging configuration to find where java8-multiarch is published. Verify that the resulting java8 tag points to the same image and avoids the stale Alpine Java 8 version; the issue names no specific file or test.

Written by the indexing model from the issue text.