Add Azul Zulu Debian repo without warnings and using `signed-by` pattern.

Dockerfile

RUN mkdir -p /etc/apt/keyrings && \
    curl -fsSL 'https://keyserver.ubuntu.com/pks/lookup?op=get&search=0xB1998361219BD9C9' | gpg --dearmor -o /etc/apt/keyrings/azul.gpg && \
    echo \
        "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/azul.gpg] https://repos.azul.com/zulu/deb stable main" \
        | tee /etc/apt/sources.list.d/zulu-openjdk.list > /dev/null && \
    apt-get update && \
    apt-get install -y zulu11-jdk && \
    apt-get clean