Adds docs for how to publish to npm (ethereum-optimism#463)

* Adds docs for how to publish to npm

* Update CONTRIBUTING.md

Co-authored-by: Faina Shalts <[email protected]>

* Update docs based on review

---------

Co-authored-by: Faina Shalts <[email protected]>

CONTRIBUTING.md

@@ -25,3 +25,32 @@ Once ready for review, make sure to include a thorough PR description to help re
 We use the `git rebase` command to keep our commit history tidy.
 Rebasing is an easy way to make sure that each PR includes a series of clean commits with descriptive commit messages
 See [this tutorial](https://docs.gitlab.com/ee/topics/git/git_rebase.html) for a detailed explanation of `git rebase` and how you should use it to maintain a clean commit history.
+
+### Versioning
+
+When we need to fix bugs or introduce new features in our npm packages, we update the package version. To ensure consistency and simplicity in this process, we use a tool called [changesets](https://github.com/changesets/changesets).
+
+Each changeset contains three key pieces of information:
+* The package(s) to be published
+* Whether the release is [major, minor, or a patch](https://semver.org/)
+* A description of the change, which will be added to the autogenerated CHANGELOG.md file for the package.
+
+Once you are ready to start the process of publishing your changes to npm, you can simply run `pnpm changeset`. This command will guide you through the process of selecting packages and defining the changes. Once complete, a new file will be generated, which you need to commit to the repository. Here's an [example changeset](https://github.com/ethereum-optimism/ecosystem/blob/500f8ec30fbeda4bd675457f68e3f877f2533a03/.changeset/purple-rocks-destroy.md?plain=1).
+
+When the changeset is merged into the main branch, two GitHub actions will trigger:
+
+**[Release Snapshot](https://github.com/ethereum-optimism/ecosystem/blob/main/.github/workflows/release-snapshot.yml)**
+
+This action publishes a snapshot of the package(s) to npm. The version number will follow a pattern like `0.0.0-main-20240906142838` instead of a standard [semver version](https://semver.org/).
+
+**[Release Version](https://github.com/ethereum-optimism/ecosystem/blob/main/.github/workflows/release.yml)**
+
+This action looks for changesets on the main branch and automatically [opens a new pull request](https://github.com/ethereum-optimism/ecosystem/pull/462). This PR will:
+
+* Delete changeset files related to the current release
+* Bump the package version
+* Update the autogenerated CHANGELOG.md for the package(s)
+
+**Once this PR is merged, the release will be published to npm.**
+
+