fix: remove void from test extension points

allow downstream suites to override public tests and hooks without
native return declarations.

fixes #123

Author: cryptiklemur

.php-cs-fixer.dist.php

@@ -12,5 +12,6 @@
     ->setRules([
         '@Symfony' => true,
         'protected_to_private' => false,
+        'void_return' => false,
     ])
     ->setFinder($finder);

phpstan.neon

@@ -2,6 +2,10 @@ parameters:
     level: 9
     phpVersion: 80200
     treatPhpDocTypesAsCertain: false
+    ignoreErrors:
+        -
+            message: '#^Method Cache\\IntegrationTests\\(?:Tests\\)?(?:CachePoolTest|HierarchicalCachePoolTest|SimpleCacheTest|TaggableCachePoolTest)::(?:advanceTime|setupService|tearDownService|test[A-Z][A-Za-z0-9_]*)\(\) has no return type specified\.$#'
+            identifier: missingType.return
     paths:
         - src
         - tests