PROPOSAL: use code of conduct email

[wlandau]

The code of conduct at https://r-multiverse.org/conduct.html currently lists my individual open-source email address as the primary mode of contact. We now have conduct@r-multiverse.org, and I propose we use that email address as the contact point instead.

If we agree (or abstain), than as per our governance, this proposal will go into effect on March 28.

[wlandau]

As part of this proposal, I suggest we add mention of the code of conduct committee as a role in our governance policy.

[wlandau]

Implemented in r-multiverse/r-multiverse.github.io#68