[YAML] Pin Fleet-maintained apps to a specific version (#35972)

Related to:

- #31919

Author: marko-lisica

docs/Configuration/yaml-files.md

@@ -514,6 +514,7 @@ software:
       setup_experience: true
   fleet_maintained_apps:
     - slug: slack/darwin
+      pin_version: "4.47.59"
       install_script:
         path: ../lib/software/slack-install-script.sh
       uninstall_script:
@@ -594,14 +595,15 @@ Currently, one app for each of an App Store app's supported platforms are added,
 
 - `fleet_maintained_apps` is a list of Fleet-maintained apps. Provide the `slug` field to include a Fleet-maintained app on a team. To find the `slug`, head to **Software > Add software** and select a Fleet-maintained app, then select **Show details**. You can also see the [list of app slugs on GitHub](https://github.com/fleetdm/fleet/blob/main/ee/maintained-apps/outputs/apps.json).
 
-Currently, Fleet-maintained apps will be updated to the latest version published by Fleet when GitOps runs.
+By default, Fleet-maintained apps will be updated to the latest version published by Fleet when GitOps runs.
 
 The below fields are all optional.
 
 - `self_service` specifies whether end users can install from **Fleet Desktop > Self-service**.
 - `pre_install_query.path` is the osquery query Fleet runs before installing the software. Software will be installed only if the [query returns results](https://fleetdm.com/tables).
 - `post_install_script.path` is the script that, if supplied, Fleet will run on hosts after the software installs.
 - `icon.path` is a relative path to the PNG icon that will be displayed in Fleet and on **Fleet Desktop > Self-service** instead of the default icon the icon sourced from Apple. It must be a square PNG with dimensions between 120x120 px and 1024x1024 px. Custom icons will only override the icon for the software title and team where they are added.
+- `pin_version` specifies the version of the package that will be downloaded by Fleet. Version can be set only to the version that is available in [the app's metadata on GitHub](https://github.com/fleetdm/fleet/tree/main/ee/maintained-apps/outputs). If version isn't specified, Fleet downloads the latest version as soon as it's available in the app's metadata.
 
 The below fields are optional, and if omitted will default to values specified in [the app's metadata on GitHub](https://github.com/fleetdm/fleet/tree/main/ee/maintained-apps/outputs).
 

website/config/routes.js

@@ -1012,6 +1012,7 @@ module.exports.routes = {
   'GET /learn-more-about/built-in-variables': '/docs/configuration/yaml-files#variables',
   'GET /learn-more-about/apple-available-os-updates': 'guides/enforce-os-updates',
   'GET /learn-more-about/disable-entra-conditional-access': '/guides/entra-conditional-access-integration#disable',
+  'GET /learn-more-about/available-fma-versions': 'https://github.com/fleetdm/fleet/tree/main/ee/maintained-apps/outputs',
 
   // Sitemap
   // =============================================================================================================