Document process for releasing a library

[xinnanyemm]

Create a document that includes the instructions we give at the end of the README for the module template (and thus all of our repos). This way, we can just link to this document from all of our repos instead of pasting those instructions over and over.

[xinnanyemm]

Hey team! Please add your planning poker estimate with Zenhub @cryptodev-2s @Gudahtt @kanthesha @MajorLift @mikesposito

[Gudahtt]

This task is for documenting the release process for single-package repositories specifically. Our monorepo release documentation for core is within core.

Note that this documentation is already in the README of our module template (here) and in the README of many other repositories. This task would be to centralize this in our contributor documentation and make whatever other improvements seem appropriate.

However we have a few different scenarios across our repositories that we should account for here as well:

• Fully automated with Slack notifications (as reflected in the current module template instructions)
• Fully automated without Slack notifications
• Partially automated (GitHub release publishing is automated but not npm publishing)
• Fully manual publishing

The instructions for the very last step are a little different for these three cases.

The module template instructions apply for fully-automated repositories with Slack notifications.

For repositories without Slack notifications, we should add that the person preparing/merging the release should ping the @metamask-npm-publishers group on Slack to ask for the package to be published to npm

For fully manual releases, the person preparing the release should also manually create the GitHub release and tag first, after merging the release but before pinging the npm publishers group.