Update CODEOWNERS to AllenCell team

[jessicasyu]

Problem

The current CODEOWNERS points to a team that existed in previous organization. When this repo was migrated to AllenCell, it no longer had access to this team, and therefore the CODEOWNERS file could not assign reviewers.

Solution

Added a new team AllenCell/simviz-web-devs with membership matching the original team, and updated CODEOWNERS to point to this team.

Type of change

• Bug fix (non-breaking change which fixes an issue)

[toloudis]

it should be noted that this is a Python package and not really something that web devs would review, at least if you go by the team name

[jessicasyu]

@toloudis I don't feel strongly about the team name, happy to change or add a separate simviz-python-devs team?

[ShrimpCryptid]

@jessicasyu I think this is fine! We can keep it as web-devs for now, and change it to Python if we have another SimViz Python repo that's being actively developed