chore: Add RELEASE instructions

Closes: cloudevents#40
Signed-off-by: Michael Gasch <[email protected]>

RELEASE.md

@@ -0,0 +1,57 @@
+# How to create a Release
+
+We use `tags` to drive the creation of the releases. This is handled by the
+Github Actions release workflow in
+[`ps-ce-sdk-release.yaml`](.github/workflows/ps-ce-sdk-release.yaml).
+
+A new release will upload the `PowerShell` module artifacts to the `PowerShell`
+[gallery](https://www.powershellgallery.com/packages/CloudEvents.Sdk).
+
+## Step 1 - Bump Module Version
+
+Bump the `ModuleVersion` in
+[`src/CloudEventsPowerShell/CloudEvents.Sdk.psd1`](./src/CloudEventsPowerShell/CloudEvents.Sdk.psd1)
+to the next semantic release version (without `"v"` prefix).
+
+```powershell
+# Version number of this module.
+ModuleVersion = '0.3.0'
+```
+
+Create a pull request with this change, review and approve it **after** all checks
+have passed.
+
+
+## Step 2 - Update local `main` branch
+
+Pull in the latest changes, incl. the merged PR above, into your local `main`
+branch of this repository **before** creating a `tag` via the `git` CLI.
+
+```console
+git checkout main
+git fetch -avp
+git pull upstream main
+```
+
+**Note:** the above commands assume `upstream` pointing to the remote
+`https://github.com/cloudevents/sdk-powershell.git`
+
+## Step 3 - Create and push a Tag
+
+
+```console
+RELEASE=v0.3.0
+git tag -a $RELEASE -m "Release ${RELEASE}"
+git push upstream refs/tags/${RELEASE}
+```
+
+
+This will trigger the release
+[workflow](https://github.com/cloudevents/sdk-powershell/actions/workflows/ps-ce-sdk-release.yaml).
+**Verify** that it executed successfully and that a new Github
+[release](https://github.com/cloudevents/sdk-powershell/releases) was created.
+
+The release workflow also creates a pull request with the updated
+[`CHANGELOG.md`](CHANGELOG.md). **Verify**, approve and merge accordingly.
+
+If you need to make changes to the Github release notes, you can edit them on the [release](https://github.com/cloudevents/sdk-powershell/releases) page.