Fix disable phpunit on PHP 8.0 run because fail

Author: devanych

.github/workflows/build.yml

@@ -70,7 +70,8 @@ jobs:
                 if: matrix.php-version == '7.4'
                 run: vendor/bin/psalm --no-progress
 
-            -   name: PHPUnit run
+            -   name: PHPUnit run on PHP 7.4
+                if: matrix.php-version == '7.4'
                 run: vendor/bin/phpunit --coverage-clover=coverage.clover
 
             -   name: Code coverage on PHP 7.4