fix: Update ossrh release repository

[fabriziodemaria]

Latest release PR triggered the following steps in CI:

[INFO] Uploading to ossrh: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/spotify/confidence-openfeature-provider/0.0.1/confidence-openfeature-provider-0.0.1.jar
[INFO] Uploaded to ossrh: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/spotify/confidence-openfeature-provider/0.0.1/confidence-openfeature-provider-0.0.1.jar (381 kB at 47 kB/s)
[INFO] Uploading to ossrh: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/spotify/confidence-openfeature-provider/0.0.1/confidence-openfeature-provider-0.0.1.pom
[INFO] Uploaded to ossrh: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/spotify/confidence-openfeature-provider/0.0.1/confidence-openfeature-provider-0.0.1.pom (10 kB at 60 kB/s)
[INFO] Downloading from ossrh: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/spotify/confidence-openfeature-provider/maven-metadata.xml
[INFO] Uploading to ossrh: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/spotify/confidence-openfeature-provider/maven-metadata.xml
[INFO] Uploaded to ossrh: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/spotify/confidence-openfeature-provider/maven-metadata.xml (322 B at 1.9 kB/s)

The upload was successful, but the artefact is not discoverable in the "releases" repository (also reachable here). It's possible it just takes some time for the artifact to be discoverable (but this is unlikely to be the problem, since I checked more than one hour after the upload).

If the problem persists, this PR suggests a way to upload directly to "releases", bypassing "staging". Note that this change is not backed by the official documentation, that rather indicates to use the distributionManagement we currently have in main.

In another WIP branch, we are experimenting using the official nexus-staging-maven-plugin for deployments, if this problem persists in the current setup.