Adding release info

RELEASE.md

@@ -0,0 +1,9 @@
+# Release
+
+To create a new release on NPM you need to create a [release](https://docs.github.com/en/repositories/releasing-projects-on-github/managing-releases-in-a-repository#creating-a-release) on Github and the [release.yml](.github/workflows/release.yml) action will then deploy a release on NPM. 
+
+This requires NPM_TOKEN to be setup as a repository secret. This will update the package at:
+
+https://www.npmjs.com/package/@iiif/3d-manifesto-dev
+
+To update the version number in NPM you will also need to update the version number in [package.json](package.json).