docs: stop readers adding a custom endpoint to install the bundle (#37)

The bundle's Flex recipe landed in `symfony/recipes-contrib`
([#2014](symfony/recipes-contrib#2014), merged
2026-07-20). A plain `composer require soviann/deploy-tasks-bundle` now
applies the recipe once Contrib recipes are enabled — no custom Composer
endpoint required.

This rewrites the README "Flex recipe" section to lead with the
published recipe and `extra.symfony.allow-contrib`, and demotes the
`Soviann/flex-recipes` endpoint to an optional fallback in a `<details>`
block for anyone who prefers not to enable Contrib recipes globally.

Verified end-to-end: a fresh `symfony/skeleton` with `allow-contrib` +
plain `composer require` scaffolds config, host runner, and gitignore
from `github.com/symfony/recipes-contrib:main`.

Docs-only — no CHANGELOG entry (bundle code/API unchanged; the recipe
lives in recipes-contrib, not the package).

Author: Soviann

README.md

@@ -31,13 +31,24 @@ return [
 
 ### Flex recipe
 
-The bundle's Flex recipe is served from a dedicated endpoint until it lands in `symfony/recipes-contrib`. To use it, add the endpoint before requiring the bundle:
+The bundle's [Flex recipe](https://github.com/symfony/recipes-contrib/tree/main/soviann/deploy-tasks-bundle) lives in `symfony/recipes-contrib`. When Contrib recipes are enabled, `composer require soviann/deploy-tasks-bundle` registers the bundle, publishes `config/packages/soviann_deploy_tasks.yaml`, installs the host runner (`bin/deploy-tasks-host.sh`), and adds the host-task `.gitignore` entries automatically. Flex asks once per project before running a Contrib recipe — answer yes, or enable them permanently:
+
+```bash
+composer config extra.symfony.allow-contrib true
+```
+
+The recipe is optional — without it, the bundle works with its default configuration, and `deploytasks:host:install` scaffolds the host runner on demand.
+
+<details>
+<summary>Alternative: dedicated recipe endpoint</summary>
+
+Prefer not to enable Contrib recipes globally? The same recipe is also served from a dedicated endpoint:
 
 ```bash
 composer config extra.symfony.endpoint --json '["https://api.github.com/repos/Soviann/flex-recipes/contents/index.json", "flex://defaults"]'
 ```
 
-With the endpoint enabled, `composer require soviann/deploy-tasks-bundle` registers the bundle, publishes `config/packages/soviann_deploy_tasks.yaml`, installs the host runner (`bin/deploy-tasks-host.sh`), and adds the host-task `.gitignore` entries automatically. The recipe is optional — without it, the bundle works with its default configuration, and `deploytasks:host:install` scaffolds the host runner on demand.
+</details>
 
 ## Quick Start