I know you tried it with
apt-get --allow-releaseinfo-change update
but it worked for me.
This is my command in the dockerfile:
wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add - \
&& sh -c 'echo "deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list' \
&& apt-get --allow-releaseinfo-change update \
&& apt-get install -y google-chrome-unstable \
--no-install-recommends \
&& rm -rf /var/lib/apt/lists/*
not required: rm -rf /var/lib/apt/lists/*