Merge pull request #672 from Dyalog/671-document-release-process

Add instructions on how to make releases

Closes #671

RELEASE.md

@@ -0,0 +1,10 @@
+# Making Link releases
+
+Link releases are handled via a [GitHub Action](https://docs.github.com/en/actions); see `.github/workflows/make-link-release.yml` for the details. It will create a new release upon detecting a new tag beginning with the letter "v". For example, if you want to create a new release `v4.0.18`, do the following:
+```
+git tag v4.0.18
+git push origin v4.0.18
+```
+and the release should get baked. A release will contain two assets, one for Dyalog version `18.2`, and one for version `19` and later.
+
+Note that the action does NOT validate the release sequence in any way. It is up to the person making the release to compose the tag appropriately.