Update documentation to reflect Laravel 8 support

docs/.sections/getting-started/environment-requirements.md

@@ -1,7 +1,7 @@
 ## Getting started
 
 ### Environment requirements
-Twill is compatible with Laravel versions `5.6` to `7`, running on PHP 7.1 and above.
+Twill is compatible with Laravel versions `5.6` to `8`, running on PHP 7.1 and above.
 
 As a dependency to your own application, Twill shares Laravel's [server requirements](https://laravel.com/docs/6.x/installation#server-requirements), which are satisfied by both [Homestead](https://laravel.com/docs/7.x/homestead) and [Valet](https://laravel.com/docs/7.x/valet) during development, and easily deployed to production using [Forge](https://forge.laravel.com) and [Envoyer](https://envoyer.io) or [Envoy](https://laravel.com/docs/7.x/envoy), as well as any other Laravel compatible server configuration and deployment strategy.
 
@@ -14,7 +14,7 @@ In summary:
 |            | Supported versions | Recommended version |
 |:-----------|:------------------:|:-------------------:|
 | PHP        | >= 7.1             | 7.4                 |
-| Laravel    | >= 5.6             | 7                   |
+| Laravel    | >= 5.6             | 8                   |
 | npm        | >= 5.7             | 6.13                |
 | MySQL      | >= 5.7             | 5.7                 |
 | PostgreSQL | >= 9.3             | 10                  |

docs/.sections/preface.md

@@ -60,7 +60,7 @@ Built to get out of your way, Twill offers:
 
 #### Developer experience
 * Maintain a Laravel application, not a Twill application
-* Support for Laravel 5.6 to 6 and will be updated to support all future versions
+* Support for Laravel 5.6 and up – Twill will be updated to support all future versions
 * Support for both MySQL and PostgreSQL databases
 * No conflict with other Laravel packages – keep building with your tools of choice
 * No specific server requirements, if you can deploy a Laravel application, you can deploy Twill