Jupyter Pyspark Toree Add-On Docker Builder

Python dependencies to install over
jupyter-pyspark-toree-docker.

Support for Python 2.7 has been removed, due to difficulty in installing
koalas (and possibly other packages in the future due to EOL).

List of Python 3 dependencies installed

For Linux user, you can download Tera CLI v0.4 at
https://github.com/guangie88/tera-cli/releases and place it in PATH.

Otherwise, you will need cargo, which can be installed via
rustup.

Once cargo is installed, simply run cargo install tera-cli --version=^0.4.0.

Always make changes in templates/ci.yml.tmpl since the template will be
applied onto .github/workflows/ci.yml.

Run templates/apply-vars.sh to apply the template once tera-cli has been
installed.