[2.9] Drop support for: Laravel 6, Laravel 7, PHP 7.2 and add doctrine/dbal ^3 (#1114)

* composer.json: drop support for PHP 7.2/Laravel 6+7 and bump dependencies

* tests: remove framework version tests

They don't apply anymore, we're Laravel 8+ only from now on

* changelog: update for ending support for L6/7 and PHP7.2

.github/workflows/run-integration-tests.yml

@@ -18,15 +18,8 @@ jobs:
             COMPOSER_NO_INTERACTION: 1
         strategy:
             matrix:
-                php: [8.0, 7.4, 7.3, 7.2]
-                lumen: [8.*, 7.*, 6.*]
-                exclude:
-                  - lumen: 6.*
-                    php: 8.0
-                  - lumen: 7.*
-                    php: 8.0
-                  - lumen: 8.*
-                    php: 7.2
+                php: [8.0, 7.4, 7.3]
+                lumen: [8.*]
         name: P${{ matrix.php }} - Lumen${{ matrix.lumen }}
         steps:
             - name: Checkout code
@@ -82,11 +75,8 @@ jobs:
             COMPOSER_NO_INTERACTION: 1
         strategy:
             matrix:
-                php: [7.4, 7.3, 7.2]
-                laravel: [8.*, 7.*, 6.*]
-                exclude:
-                  - laravel: 8.*
-                    php: 7.2
+                php: [8.0, 7.4, 7.3]
+                laravel: [8.*]
         name: P${{ matrix.php }} - Laravel${{ matrix.laravel }}
         steps:
             - name: Checkout code