Publish package on PyPI so that it can be installed by research_index_frontend

[willu47]

At present, ClimateCompatibleGrowth/research_index_frontend installs the research_index package directly from the main branch on Github. This is not very robust, and it should reference a tagged version on PyPi instead.

• Add a github action to continuosly deploy to PyPI
• Deployment should occur on tagged versions on the main branch