Test multiple PHPUnit versions

Author: ondrejmirtes

.github/workflows/build.yml

@@ -97,6 +97,10 @@ jobs:
         dependencies:
           - "lowest"
           - "highest"
+        phpunit-version:
+          - "^9.5"
+          - "^10.5"
+          - "^11.5"
 
     steps:
       - name: "Checkout"
@@ -108,6 +112,9 @@ jobs:
           coverage: "none"
           php-version: "${{ matrix.php-version }}"
 
+      - name: "Require specific PHPUnit version"
+        run: "composer require --dev phpunit/phpunit:${{ matrix.phpunit-version }}"
+
       - name: "Install lowest dependencies"
         if: ${{ matrix.dependencies == 'lowest' }}
         run: "composer update --prefer-lowest --no-interaction --no-progress"
@@ -136,6 +143,10 @@ jobs:
         dependencies:
           - "lowest"
           - "highest"
+        phpunit-version:
+          - "^9.5"
+          - "^10.5"
+          - "^11.5"
 
     steps:
       - name: "Checkout"
@@ -149,6 +160,9 @@ jobs:
           extensions: mbstring
           tools: composer:v2
 
+      - name: "Require specific PHPUnit version"
+        run: "composer require --dev phpunit/phpunit:${{ matrix.phpunit-version }}"
+
       - name: "Install lowest dependencies"
         if: ${{ matrix.dependencies == 'lowest' }}
         run: "composer update --prefer-lowest --no-interaction --no-progress"