doc: doc how to add message for promotion · nodejs/node@36080b7

in the OpenJS Slack. For that reason and for communication purposes and

collaboration opportunities, ambassadors should be members of the

[OpenJS Slack](https://slack-invite.openjsf.org/).

## Messages and topics to promote

### How to add messages or topics to promote

Messages or topics that ambassadors are asked to promote are added to this

document in the [Current messages for promotion](#current-messages-for-promotion)

section through the standard PR process except that they should be open

for 7 days before landing and should include and at mention to the

nodejs/TSC for awareness. They should be removed through the same process

when no longer relevant.

### Current messages for promotion

#### Sample message (Leave this one at the top)

##### Goal

The goal is to raise awareness of XYZ in the JavaScript ecosystem.

#### Related Links

List of links with more information about the topic to provide brackground

or the information to be shared.

#### Project contacts

Add a list of GitHub handles for those within the project that

have volunteered to be contacated when necessary by ambassadors

to get more info about the message to be promoted.