RELEASE.md: add release guide

Author: estroz

RELEASE.md

@@ -0,0 +1,41 @@
+# Releasing
+
+Releases of this repo target [semver][semver] tags pushed by repo admins.
+To request a release, please ping an admin on [#olm-dev][slack-olm-dev]
+or [#operator-sdk-dev][slack-osdk-dev] Kubernetes Slack channels, or
+post to the [operator-framework group][of-ggroup].
+
+## Tags
+
+As per semver, all releases containing new features must map to a major or minor version increase.
+Patch releases must only contain fixes to features released in a prior release.
+
+## Process
+
+In your local shell (assuming you have repo admin privileges):
+
+```sh
+export PREVIOUS_RELEASE_TAG=$(git describe --tags --abbrev=0)
+export RELEASE_TAG="vX.Y.Z"
+git checkout master
+git pull master
+git fetch --all
+git tag $RELEASE_TAG
+# Assuming the 'upstream' remote points to the operator-framework repo.
+git push upstream refs/tags/$RELEASE_TAG
+```
+
+Then create release notes while still on the `master` branch:
+
+```sh
+while read -r line; do echo $line | awk '{f = $1; $1 = ""; print "-"$0; }'; done <<< $(git log $PREVIOUS_RELEASE_TAG..$RELEASE_TAG --format=oneline --no-merges)
+```
+
+Copy them into the Github release [description form][release-desc-page],
+select `vX.Y.Z` in the `Tag version` form, and click `Publish release`.
+
+[semver]:https://semver.org/
+[slack-olm-dev]:https://kubernetes.slack.com/messages/olm-dev
+[slack-osdk-dev]:https://kubernetes.slack.com/messages/operator-sdk-dev
+[of-ggroup]:https://groups.google.com/forum/#!forum/operator-framework
+[release-desc-page]:https://github.com/operator-framework/api/releases/new