fix(build): publish Maven artifacts under hyperledger-identus namespace

[patextreme]

Why

Follow-up to #18 (which migrated the Docker image namespace). The first release run after #18 (run 30343777327) failed — semantic-release computed `0.2.1` correctly, but `sbt release`'s `publishArtifacts` step 404'd while publishing the jar+POM:

```
[publish] java.io.FileNotFoundException:
https://maven.pkg.github.com/hyperledger/identus-keycloak-plugins/.../0.2.1/identus-keycloak-oid4vci-0.2.1.pom
```

sbt-github-packages publishes to `maven.pkg.github.com//`, and those were still the legacy `hyperledger`/`identus-keycloak-plugins` — the same orphaned namespace as the Docker image.

Fix

Point `githubOwner`/`githubRepository` at the current repo (`hyperledger-identus`/`keycloak-plugins`), so the Maven publish — and the Docker image push that follows it in the same release — can complete.

No release/tag was created by the failed run (semantic-release is transactional; `version.sbt` is still `0.2.0-SNAPSHOT`), so re-running `release.yml` after this merge will still cut 0.2.1.

Notes for reviewer

• Same signed-commit requirement on `main` — merge needs a signing setup.
• Dependency resolution is unaffected: all deps are `org.keycloak:*` from Maven Central; the GitHub Packages resolver is only a fallback.
• README badge URLs (lines 3–4) and the Maven-packages doc link (line 75) still point at the old `github.com/hyperledger/` paths — pre-existing cosmetic issues, left for a separate doc cleanup.

[patextreme]

Superseded — going with option C: stop publishing the Maven jar entirely (nothing consumes it; only the Docker image is needed). The githubOwner/githubRepository namespace is then moot.