CI: Fix PHP7.4 build (#327)

Author: staabm

src/Rules/PHPUnit/TestMethodsHelper.php

@@ -10,7 +10,7 @@
 use PHPStan\Type\FileTypeMapper;
 use PHPUnit\Framework\TestCase;
 use function array_key_exists;
-use function str_starts_with;
+use function strpos;
 use function strtolower;
 
 final class TestMethodsHelper
@@ -62,7 +62,7 @@ public function getTestMethods(ClassReflection $classReflection, Scope $scope):
 				continue;
 			}
 
-			if (str_starts_with(strtolower($reflectionMethod->getName()), 'test')) {
+			if (strpos(strtolower($reflectionMethod->getName()), 'test') === 0) {
 				$testMethods[] = $reflectionMethod;
 				continue;
 			}

src/Type/PHPUnit/DynamicCallToAssertionIgnoreExtension.php

@@ -8,7 +8,7 @@
 use PHPStan\Analyser\Scope;
 use PHPUnit\Framework\TestCase;
 use function is_string;
-use function str_starts_with;
+use function strpos;
 
 final class DynamicCallToAssertionIgnoreExtension implements IgnoreErrorExtension
 {
@@ -33,7 +33,7 @@ public function shouldIgnore(Error $error, Node $node, Scope $scope): bool
 
 		if (
 			!$node->name instanceof Node\Identifier
-			|| !str_starts_with($node->name->name, 'assert')
+			|| strpos($node->name->name, 'assert') !== 0
 		) {
 			return false;
 		}