DeepChem Updates of April (Week 1), 2024

Here is a quick summary of merged pull requests for DeepChem during the first week of April:

1. Add 2.8.1 dev tag for development: This PR updates version to 2.8.1 dev and implements a trial fix for references issues in rendering.
2. V2.8.0 minor fixes for release: This PR fixes minor issuess for release.
3. bump up deepchem version to 2.8.0: This PR updates DeepChem to version 2.8.0 for release. It fixes several issues including docker out of storage error, inconsistencies in docs and env files, and seeding of doctest.