chore: changed agent base image to own alpine-base

Dockerfile

@@ -44,6 +44,3 @@ RUN set -o errexit -o nounset && echo "Installing build dependencies" && \
     echo "Editing startGroovy to include java.xml.bind module" &&  \
     sed --in-place 's|startGroovy ( ) {|startGroovy ( ) {\n JAVA_OPTS="$JAVA_OPTS --add-modules=ALL-SYSTEM"|' "${GROOVY_HOME}/bin/startGroovy"
 
-RUN apk add --no-cache openssh-client
-
-COPY --from=docker/buildx-bin /buildx /usr/libexec/docker/cli-plugins/docker-buildx