chore: add standard-version and release script

[lance]

This commit adds the standard-version module for managing releases.
When running npm run release the following steps are taken.

1. Retreive the current version of your repository by looking at package.json.
2. Bump the version in package.json based on the commits.
3. Prepends to the CHANGELOG based on the commits (uses conventional-changelog under the hood).
4. Create a new commit including the package.json and updated CHANGELOG.
5. Create a new tag with the new version number.

This works best if all commits follow the Conventional Commits specification.
https://www.conventionalcommits.org/en/v1.0.0/

Fixes: #56

[grant]

Looks good to me besides the conflicts.

[fabiojose]

@lance could you fix the conflicts and remove the package-lock.json?

[lance]

@fabiojose conflicts have been resolved.

I suggest keeping package-lock.json. It was intentionally added by me in aa2cef6. Standard best practices (and npm documentation recommend keeping these in your source repositories.

[grant]

Looks mergeable to me. Please keep the lock as is standard practice. 👍
Will wait for Fabio's response.

[lance]

@fabiojose do you think it would be possible to avoid doing a Merge commit on these, but instead do a Squash and Merge or Squash and Rebase? When performing merge commits, we get commits in the commit log that look like this:

Merge pull request #55 from lance/54-add-linter …

A squash and merge will make it so that the commit log is cleaner, with only messages like this:

src: add eslint configuration and npm script …

For standard-version to automatically format and document the changelog, it's best if all commits in the commit log follow the Conventional Commits spec. thanks!

[fabiojose]

Yes, off course!

[grant]

@fabiojose do you think it would be possible to avoid doing a Merge commit on these, but instead do a Squash and Merge or Squash and Rebase? When performing merge commits, we get commits in the commit log that look like this:

Merge pull request #55 from lance/54-add-linter …

A squash and merge will make it so that the commit log is cleaner, with only messages like this:

src: add eslint configuration and npm script …

For standard-version to automatically format and document the changelog, it's best if all commits in the commit log follow the Conventional Commits spec. thanks!

I've disabled merge commits and only allowed squash/rebase.

[fabiojose]

@lance could you update the section Changelog at https://github.com/cloudevents/sdk-javascript/blob/master/CONTRIBUTING.md?

Please add links or tips for incoming contributors.