fix dependency installation

[stevenhua0320]

Closes #109

[bobleesj]

@stevenhua0320 Hi Steven,

In workflows/main.yml,

please change the line from

pip install .

to

pip install . --no-deps

We do not want the CI to re-install all of the dependencies again once we have already installed them via conda.

Reference: https://github.com/Billingegroup/bg-mpl-stylesheets/pull/60/files