docs: Document releases. Closes #5379 (#5402)

Signed-off-by: Alex Collins <alex_collins@intuit.com>

docs/releases.md

@@ -0,0 +1,28 @@
+# Releases
+
+## Supported Versions
+
+Versions are expressed as x.y.z, where x is the major version, y is the minor version, and z is the patch version,
+following Semantic Versioning terminology.
+
+We maintain release branches for the most recent two minor releases.
+
+Fixes may be backported to release branches, depending on severity, risk, and, feasibility.
+
+If a release contains breaking changes, or CVE fixes, this will documented in the release notes.
+
+## Supported Version Skew
+
+Both the `argo-server` and `argocli` should be the same version as the controller.
+
+# Release Cycle
+
+For **unstable**, we build and tag `latest` images for every commit to master.
+
+New major versions are released roughly every 3 months. Release candidates for each major release are typically available
+for 6 weeks before the release becomes generally available.
+
+Otherwise, we typically release once a week:
+
+* Patch fixes for the current stable version. These are tagged `stable`.
+* The next release candidate, if we are currently in a release-cycle.

mkdocs.yml

@@ -123,6 +123,7 @@ nav:
           - argo watch: cli/argo_watch.md
   - Operator Manual:
       - installation.md
+      - releases.md
       - Configuration:
           - managed-namespace.md
           - configure-artifact-repository.md