add sanity testing workflow and docs

Signed-off-by: Florian Wagner <h2floh@github.com>

docs/RELEASE.md

@@ -0,0 +1,40 @@
+# Release process
+
+When we want to do a new release, push a git tag with format `v**` and workflow `releases.yml` executes.
+
+This workflow internally uses [go-releaser](https://goreleaser.com/ci/actions/) to push a new release.
+
+Please follow the below detailed steps.
+- Create a tag in format `v202205240715`
+```code
+git tag -a `date "+v%Y%m%d%H%M"` -m "Release a new version"
+```
+- Get the tag name
+```code
+git tag
+```
+- Push the newly created tag
+```code
+git push origin <tag>
+```
+- Check workflow `releases.yml` should trigger
+- Once completed, go to repo releases page and edit the newly created release as `pre-release`, so we can do sanity testig before we officicaly release
+- Recommend to do basic sanity testing (see below) on the new release.
+- Once sanity testing is done, we can edit the releas and mark it as `Latest version` and edit the release notes.
+
+## Basic Sanity testing
+
+### Prerequisite
+
+1. Access to a GHES test server
+1. Create a PAT token with `site-admin` scope in the GHES environment for `ghe-admin`
+
+### Execution
+
+1. Update below Repository level secrets:
+
+    - sanity_test_site_admin_token: The PAT generated earlier 
+    - sanity_test_ghes_url: The URL to the GHES instance 
+    - sanity_test_releasedatetime: The datetime string for the release to test without the `v` (e.g. `202211070205`)
+
+1. Manually trigger this workflow: https://github.com/actions/actions-sync/actions/workflows/actions-sync-e2e-test-caller.yml