Drop Laravel 11, add PHP 8.5 and merge CI workflows

- Require Laravel 12 or 13 and drop orchestra/testbench 9
- Add PHP 8.5 to the test matrix
- Merge the test and PHPStan workflows into a single CI workflow,
  running PHPStan before the test matrix
- Add manual dispatch and cancel superseded runs
- Update requirements and badge in README

.github/workflows/ci.yml

@@ -1,52 +1,59 @@
-name: run-tests
+name: CI
 
 on:
   push:
     paths:
       - '**.php'
-      - '.github/workflows/run-tests.yml'
+      - '.github/workflows/ci.yml'
       - 'phpunit.xml.dist'
+      - 'phpstan.neon.dist'
+      - 'phpstan-baseline.neon'
       - 'composer.json'
       - 'composer.lock'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
-  test:
-    runs-on: ${{ matrix.os }}
+  phpstan:
+    name: PHPStan
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.5'
+          coverage: none
+
+      - name: Install composer dependencies
+        uses: ramsey/composer-install@v3
+
+      - name: Run PHPStan
+        run: vendor/bin/phpstan --error-format=github
+
+  tests:
+    name: P${{ matrix.php }} - L${{ matrix.laravel }} - ${{ matrix.stability }}
+    needs: phpstan
+    runs-on: ubuntu-latest
     timeout-minutes: 5
     strategy:
       fail-fast: true
       matrix:
-        os: [ubuntu-latest]
-        php: [8.3, 8.4]
-        laravel: [11.*, 12.*, 13.*]
+        php: ['8.3', '8.4', '8.5']
+        laravel: ['12.*', '13.*']
         stability: [prefer-lowest, prefer-stable]
         include:
-          - laravel: 11.*
-            php: 8.3
-            testbench: 9.*
-            carbon: ^2.63
-          - laravel: 11.*
-            php: 8.4
-            testbench: 9.*
-            carbon: ^2.63
-          - laravel: 12.*
-            php: 8.3
-            testbench: 10.*
-            carbon: ^3.8.4
-          - laravel: 12.*
-            php: 8.4
-            testbench: 10.*
-            carbon: ^3.8.4
-          - laravel: 13.*
-            php: 8.3
-            testbench: 11.*
-            carbon: ^3.8.4
-          - laravel: 13.*
-            php: 8.4
-            testbench: 11.*
-            carbon: ^3.8.4
-
-    name: P${{ matrix.php }} - L${{ matrix.laravel }} - ${{ matrix.stability }} - ${{ matrix.os }}
+          - laravel: '12.*'
+            testbench: '10.*'
+          - laravel: '13.*'
+            testbench: '11.*'
 
     steps:
       - name: Checkout code
@@ -69,12 +76,12 @@ jobs:
           composer require \
             "laravel/framework:${{ matrix.laravel }}" \
             "orchestra/testbench:${{ matrix.testbench }}" \
-            "nesbot/carbon:${{ matrix.carbon }}" \
-            --no-interaction --no-update
+            "nesbot/carbon:^3.8.4" \
+            --dev --no-interaction --no-update
 
           composer update --${{ matrix.stability }} --prefer-dist --no-interaction
 
-      - name: List Installed Dependencies
+      - name: List installed dependencies
         run: composer show -D
 
       - name: Execute tests

.github/workflows/phpstan.yml

@@ -1,28 +0,0 @@
-name: PHPStan
-
-on:
-  push:
-    paths:
-      - '**.php'
-      - 'phpstan.neon.dist'
-      - '.github/workflows/phpstan.yml'
-
-jobs:
-  phpstan:
-    name: phpstan
-    runs-on: ubuntu-latest
-    timeout-minutes: 5
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Setup PHP
-        uses: shivammathur/setup-php@v2
-        with:
-          php-version: '8.4'
-          coverage: none
-
-      - name: Install composer dependencies
-        uses: ramsey/composer-install@v3
-
-      - name: Run PHPStan
-        run: ./vendor/bin/phpstan --error-format=github