chore(repo): add dev release instructions

Pull request checklist

Please check if your PR fulfills the following requirements:

[x] Docs have been reviewed and added / updated if needed (for bug fixes / features)
[ ] Build (npm run build) was run locally and any changes were pushed
[ ] Tests (npm test) were run locally and passed
[x] Prettier (npm run prettier) was run locally and passed

Pull request type

Please check the type of change your PR introduces: - [ ] Bugfix - [ ] Feature - [ ] Refactoring (no functional changes, no api changes) - [ ] Build related changes - [x] Documentation content changes - [ ] Other (please describe): ## What is the current behavior?

We don't have explicit instructions describing how to release the project

GitHub Issue Number: N/A

What is the new behavior?

add instructions for creating a dev release to the repo, similar to the stencil core repository. for now, we omit production releases from this document, as they are not currently automated.

Does this introduce a breaking change?

[ ] Yes
[x] No

Testing

I walked through these instructions and published a dev build from them/using them.

I encourage others to do the same in case something isn't clear in these instructions/if I overlooked something

ionic-team / create-stencil