Install JReleaser in release-agent

In preparation to publishing directly to Maven Central rather than going
through the now deprecated OSSH staging deployment.

Bug: Issue 450577964
Change-Id: I8a90c7819937da4759ccefd36d7e4f902e6ba981

Author: syntonyze

jenkins-docker/agent-release/Dockerfile

@@ -1,12 +1,18 @@
 FROM gerritforge/gerrit-ci-agent-bazel:debian-bookworm-nocache-latest
 
+ARG JRELEASER_VERSION=1.20.0
 RUN apt-get update --allow-releaseinfo-change && \
     apt-get install -y gnupg2 jq && \
     export CLOUD_SDK_REPO="cloud-sdk-bookworm" && \
     echo "deb http://packages.cloud.google.com/apt $CLOUD_SDK_REPO main" > /etc/apt/sources.list.d/google-cloud-sdk.list && \
     curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - && \
     apt-get update --allow-releaseinfo-change && apt-get install -y google-cloud-sdk && \
     apt-get clean
+RUN curl -fsSL -o /tmp/jr.zip \
+      "https://github.com/jreleaser/jreleaser/releases/download/v${JRELEASER_VERSION}/jreleaser-standalone-${JRELEASER_VERSION}-linux-x86_64.zip" && \
+    unzip /tmp/jr.zip -d /opt && \
+    ln -sf "/opt/jreleaser-standalone-${JRELEASER_VERSION}-linux-x86_64/bin/jreleaser" /usr/local/bin/jreleaser && \
+    rm -f /tmp/jr.zip
 
 COPY gerrit-release.sh /usr/local/bin
 COPY gerrit-upgrade-test.sh /usr/local/bin