Switch from deprecated openjdk to eclipse-temurin

[fgreinacher]

PR checklist

• [x] Read the contribution guidelines.
• [ ] ~~Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.~~ Not needed I'd say
• [x] Filed the PR against the correct branch: 3.0.0 branch for changes related to OpenAPI spec 3.0. Default: master.
• [ ] ~~Copied the technical committee to review the pull request if your PR is targeting a particular programming language.~~ Not needed I'd say

Description of the PR

The OpenJDK images have long been deprecated (see https://hub.docker.com/_/openjdk) and are built on top of EOL'd Alpine versions.

:hammer_and_pick: with :heart: by Siemens

[fgreinacher]

Deprecated image: https://hub.docker.com/layers/library/openjdk/8-jre-alpine/images/sha256-f7a292bbb70c4ce57f7704cc03eb09e299de9da19013b084f138154421918cb4?context=explore

Up-to-date image: https://hub.docker.com/layers/library/eclipse-temurin/8-jre-alpine/images/sha256-9bad051b28af89bb3ec3d7e9ffcbfe6dcf50869c77af1128a3797f39ff7271e9?context=explore

[fgreinacher]

@frantuma Would you have a look at this? 🙇

[fgreinacher]

@frantuma Friendly ping. Let me know if I can perform additional preparation/testing to make reviewing easier. 🙇

[fgreinacher]

@frantuma @HugoMario Pinging you again because we really want to avoid forking this just for getting rid of the deprecated JDK 🙇