Add git to the image

[janezj]

Some projects dependencies are loaded using git

[MonsieurV]

Indeed.

Could this be merged? @theasp

The corresponding change to the Debian based image: (with apt clean to prevent from adding apt repo data to the Docker layer)

RUN apt-get update \
  && apt-get -q -y install openjdk-11-jdk curl \
  && npm install -g shadow-cljs \
  && curl -s https://download.clojure.org/install/linux-install-$CLOJURE_VER.sh | bash \
  && apt-get clean && rm -rf /var/lib/apt/lists/*

Thanks for the image