docs: add latest prerelease build info (close #4041) (#4048)

docs/_theme/djangodocs/layout.html

@@ -515,12 +515,20 @@
           .then(function (response) {
             const data = JSON.parse(response);
             const latest_version = data.latest;
+            const latest_prerelease_version = data.prerelease;
 
-            const targets = document.getElementsByClassName('latest-release-tag');
-            for (let i = 0; i < targets.length; i++) {
-              const target = targets[i];
+            const release_targets = document.getElementsByClassName('latest-release-tag');
+            for (let i = 0; i < release_targets.length; i++) {
+              const release_target = release_targets[i];
 
-              target.innerHTML = latest_version;
+              release_target.innerHTML = latest_version;
+            }
+
+            const prerelease_targets = document.getElementsByClassName('latest-prerelease-tag');
+            for (let i = 0; i < prerelease_targets.length; i++) {
+              const prerelease_target = prerelease_targets[i];
+
+              prerelease_target.innerHTML = latest_prerelease_version;
             }
           })
           .catch(function (err) {

docs/graphql/manual/deployment/updating.rst

@@ -7,19 +7,41 @@ Updating Hasura GraphQL engine
 
 .. contents:: Table of contents
   :backlinks: none
-  :depth: 1
+  :depth: 2
   :local:
 
+Update guides
+-------------
+
 The Hasura GraphQL engine runs off a Docker image and updates are as simple as changing the image tag.
 
-The current latest version is:
-
-.. raw:: html
-
-   <code>hasura/graphql-engine:<span class="latest-release-tag">latest</span></code>
-
 Based on your deployment method, follow the appropriate guide to update the GraphQL engine version you're running:
 
 - :doc:`Updating on Heroku <heroku/updating>`
 - :doc:`Updating on Docker <docker/updating>`
 - :doc:`Updating on Kubernetes <kubernetes/updating>`
+
+Latest available versions
+-------------------------
+
+Stable version
+**************
+
+The current latest stable version is:
+
+.. raw:: html
+
+   <code>hasura/graphql-engine:<span class="latest-release-tag">latest</span></code>
+
+Pre-release version
+*******************
+
+The current latest pre-release version is:
+
+.. raw:: html
+
+   <code>hasura/graphql-engine:<span class="latest-prerelease-tag">prerelease</span></code>
+
+.. note::
+
+  Full stability with pre-release builds is not guaranteed. They are not recommended for production use.