add a contributing guide (#23)

* add a contributing guide

* Update CONTRIBUTING.md

Co-authored-by: F <f@replicate.com>

---------

Co-authored-by: F <f@replicate.com>

Author: zeke

CONTRIBUTING.md

@@ -0,0 +1,34 @@
+# Contributing
+
+**This is an early alpha. The implementation might change between versions
+without warning. Please use at your own risk and pin to a specific version if
+you're relying on this for anything important!**
+
+## Development
+
+Make sure you have a recent version of Node.js installed (`>=18`). Then run:
+
+```
+npm install
+npm test
+```
+
+## Releases
+
+To cut a new release, run:
+
+```
+cd replicate-js
+git checkout main
+git pull
+npx np minor
+```
+
+This will:
+
+- Run tests locally
+- Bump the version in `package.json`
+- Commit and tag the release
+- Push the commit and tag to GitHub
+- Publish the package to npm
+- Create a GitHub release