NO_PUBKEY error in trying to install R on Ubuntu Bionic beaver (building docker)

Question

So Googling shows up this link on travis, which seems to have happen only recently:

https://travis-ci.community/t/then-sudo-apt-get-update-failed-public-key-is-not-available-no-pubkey-6b05f25d762e3157-in-ubuntu-xenial/1728/4

Therefore I suspect that the key somehow got changed again?

==========

Background: I'm trying to change my docker file to include a new R package dependency, the base image is Ubuntu Bionic, and was hit by this error:

W: GPG error: https://packagecloud.io/github/git-lfs/ubuntu bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 6B05F25D762E3157
E: The repository 'https://packagecloud.io/github/git-lfs/ubuntu bionic InRelease' is not signed.

And the lines in my Dockerfile that raised the error is the following:

RUN DEBIAN_FRONTEND=noninteractive \
    apt-get update && apt-get full-upgrade -y && \
    apt-get install -qqy --no-install-recommends \
        libcurl4-openssl-dev libssl-dev libxml2-dev && \
    apt-get autoremove --purge -y && apt-get autoclean -y && \
    rm -rf /var/cache/apt/* /var/lib/apt/lists/* /var/tmp/* /tmp/* /usr/share/man/?? /usr/share/man/??_*
ENV APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE=DO_NOT_WARN
RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9 && \
    add-apt-repository 'deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/' && \
    DEBIAN_FRONTEND=noninteractive apt-get update && apt-get full-upgrade -y && \
    DEBIAN_FRONTEND=noninteractive apt-get install -qqy --no-install-recommends \
        r-base

And the key is E298A3A825C0D65DFD57CBB651716619E084DAB9

Anyone know if the key is somehow changed, or something else that I wasn't understanding?

Thank you very much!

UPDATE

After adding the suggested missing public key, the issue is solved. So here are the updated lines to fix the issue (note the extra key):

RUN DEBIAN_FRONTEND=noninteractive \
    apt-get update && apt-get full-upgrade -y && \
    apt-get install -qqy --no-install-recommends \
        libcurl4-openssl-dev libssl-dev libxml2-dev && \
    apt-get autoremove --purge -y && apt-get autoclean -y && \
    rm -rf /var/cache/apt/* /var/lib/apt/lists/* /var/tmp/* /tmp/* /usr/share/man/?? /usr/share/man/??_*
ENV APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE=DO_NOT_WARN
RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9 6B05F25D762E3157 && \
    add-apt-repository 'deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/' && \
    DEBIAN_FRONTEND=noninteractive apt-get update && apt-get full-upgrade -y && \
    DEBIAN_FRONTEND=noninteractive apt-get install -qqy --no-install-recommends \
        r-base