Avoid pointing users to Oracle Java if possible

[sneumann]

Hi Team ENA / webin-cli,
the README suggests to install Oracle Java:

webin-cli/README.md

Line 30 in f488855

<https://java.com/en/download/>

due to the Oracle licensing policy (https://www.mobilize.net/blog/oracle-java-licensing)
this should be avoided at all costs, and instead point to installing OpenJDK.
This issue is related to enasequence/read_docs#217
Yours,
Steffen

[corneliusroemer]

I've made a PR switching the recommendation to Adoptium (correct me if that's not good either) plus fixing the minimum Java version:

• README: fix minimum Java version, remove broken badge, point to adoptium #152